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1.
Int J Mol Sci ; 22(19)2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34638559

RESUMO

Although peroxisomes play an essential role in viral pathogenesis, and viruses are known to change peroxisome morphology, the role of genotype in the peroxisomal response to viruses remains poorly understood. Here, we analyzed the impact of wheat streak mosaic virus (WSMV) on the peroxisome proliferation in the context of pathogen response, redox homeostasis, and yield in two wheat cultivars, Patras and Pamir, in the field trials. We observed greater virus content and yield losses in Pamir than in Patras. Leaf chlorophyll and protein content measured at the beginning of flowering were also more sensitive to WSMV infection in Pamir. Patras responded to the WSMV infection by transcriptional up-regulation of the peroxisome fission genes PEROXIN 11C (PEX11C), DYNAMIN RELATED PROTEIN 5B (DRP5B), and FISSION1A (FIS1A), greater peroxisome abundance, and activation of pathogenesis-related proteins chitinase, and ß-1,3-glucanase. Oppositely, in Pamir, WMSV infection suppressed transcription of peroxisome biogenesis genes and activity of chitinase and ß-1,3-glucanase, and did not affect peroxisome abundance. Activity of ROS scavenging enzymes was higher in Patras than in Pamir. Thus, the impact of WMSV on peroxisome proliferation is genotype-specific and peroxisome abundance can be used as a proxy for the magnitude of plant immune response.


Assuntos
Resistência à Doença/imunologia , Peroxissomos/metabolismo , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Potyviridae , Triticum/imunologia , Triticum/virologia , Quitinases/metabolismo , Clorofila/metabolismo , Glucana 1,3-beta-Glucosidase/metabolismo , Oxirredução , Peroxidases/metabolismo , Peroxissomos/genética , Peroxissomos/virologia , Fenótipo , Folhas de Planta/imunologia , Folhas de Planta/virologia , Espécies Reativas de Oxigênio/metabolismo
2.
Int J Mol Sci ; 22(19)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34639023

RESUMO

Although drought and high temperature are two main factors affecting crop productivity and forest vegetation dynamics in many areas worldwide, little work has been done to describe the effects of heat combined with pre-existing drought on photochemical function in diverse plant species. This study investigated the biophysical status of photosystem II (PSII) and its dynamic responses under 2-day heat stress during a 2-week drought by measuring the polyphasic chlorophyll fluorescence rise (OJIP) kinetics. This study examined four contrasting species: a C3 crop/grass (wheat), a C4 crop/grass (sorghum), a temperate tree species (Fraxinus chinensis) and a tropical tree species (Radermachera sinica). Principal component analysis showed that the combination of heat and drought deviated from the effect of heat or drought alone. For all four species, a linear mixed-effects model analysis of variance of the OJIP parameters showed that the deviation arose from decreased quantum yield and increased heat dissipation of PSII. The results confirmed, in four contrasting plant species, that heat stress, when combined with pre-existing drought, exacerbated the effects on PSII photochemistry. These findings provide direction to future research and applications of chlorophyll fluorescence rise OJIP kinetics in agriculture and forestry, for facing increasingly more severe intensity and duration of both heat and drought events under climate change.


Assuntos
Clorofila/metabolismo , Secas , Fluorescência , Resposta ao Choque Térmico , Fenômenos Fisiológicos Vegetais , Cinética , Fotossíntese , Especificidade da Espécie
3.
Molecules ; 26(19)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34641502

RESUMO

Single-walled carbon nanotubes (SWCNT) have recently been attracting the attention of plant biologists as a prospective tool for modulation of photosynthesis in higher plants. However, the exact mode of action of SWCNT on the photosynthetic electron transport chain remains unknown. In this work, we examined the effect of foliar application of polymer-grafted SWCNT on the donor side of photosystem II, the intersystem electron transfer chain and the acceptor side of photosystem I. Analysis of the induction curves of chlorophyll fluorescence via JIP test and construction of differential curves revealed that SWCNT concentrations up to 100 mg/L did not affect the photosynthetic electron transport chain. SWCNT concentration of 300 mg/L had no effect on the photosystem II donor side but provoked inactivation of photosystem II reaction centres and slowed down the reduction of the plastoquinone pool and the photosystem I end acceptors. Changes in the modulated reflection at 820 nm, too, indicated slower re-reduction of photosystem I reaction centres in SWCNT-treated leaves. We conclude that SWCNT are likely to be able to divert electrons from the photosynthetic electron transport chain at the level of photosystem I end acceptors and plastoquinone pool in vivo. Further research is needed to unequivocally prove if the observed effects are due to specific interaction between SWCNT and the photosynthetic apparatus.


Assuntos
Nanotubos de Carbono , Ervilhas/efeitos dos fármacos , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Clorofila/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Fluorescência , Nanotubos de Carbono/química , Ervilhas/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Polímeros/química
4.
PLoS One ; 16(10): e0256984, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34618822

RESUMO

Wheat is an important global staple food crop; however, its productivity is severely hampered by changing climate. Erratic rain patterns cause terminal drought stress, which affect reproductive development and crop yield. This study investigates the potential and zinc (Zn) and silicon (Si) to ameliorate terminal drought stress in wheat and associated mechanisms. Two different drought stress levels, i.e., control [80% water holding capacity (WHC) was maintained] and terminal drought stress (40% WHC maintained from BBCH growth stage 49 to 83) combined with five foliar-applied Zn-Si combinations (i.e., control, water spray, 4 mM Zn, 40 mM Si, 4 mM Zn + 40 mM Si applied 7 days after the initiation of drought stress). Results revealed that application of Zn and Si improved chlorophyll and relative water contents under well-watered conditions and terminal drought stress. Foliar application of Si and Zn had significant effect on antioxidant defense mechanism, proline and soluble protein, which showed that application of Si and Zn ameliorated the effects of terminal drought stress mainly by regulating antioxidant defense mechanism, and production of proline and soluble proteins. Combined application of Zn and Si resulted in the highest improvement in growth and antioxidant defense. The application of Zn and Si improved yield and related traits, both under well-watered conditions and terminal drought stress. The highest yield and related traits were recorded for combined application of Zn and Si. For grain and biological yield differences among sole and combined Zn-Si application were statistically non-significant (p>0.05). In conclusion, combined application of Zn-Si ameliorated the adverse effects of terminal drought stress by improving yield through regulating antioxidant mechanism and production of proline and soluble proteins. Results provide valuable insights for further cross talk between Zn-Si regulatory pathways to enhance grain biofortification.


Assuntos
Silício/metabolismo , Triticum/fisiologia , Zinco/metabolismo , Antioxidantes/metabolismo , Clorofila/metabolismo , Secas , Silício/administração & dosagem , Estresse Fisiológico , Água/metabolismo , Zinco/administração & dosagem
5.
BMC Plant Biol ; 21(1): 416, 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34507525

RESUMO

BACKGROUND: Leaf color variation is a common trait in plants and widely distributed in many plants. In this study, a leaf color mutation in Camellia japonica (cultivar named as Maguxianzi, M) was used as material, and the mechanism of leaf color variation was revealed by physiological, cytological, transcriptome and microbiome analyses. RESULTS: The yellowing C. japonica (M) exhibits lower pigment content than its parent (cultivar named as Huafurong, H), especially chlorophyll (Chl) and carotenoid, and leaves of M have weaker photosynthesis. Subsequently, the results of transmission electron microscopy(TEM) exhibited that M chloroplast was accompanied by broken thylakoid membrane, degraded thylakoid grana, and filled with many vesicles. Furthermore, comparative transcriptome sequencing identified 3,298 differentially expressed genes (DEGs). KEGG annotation analysis results showed that 69 significantly enriched DEGs were involved in Chl biosynthesis, carotenoid biosynthesis, photosynthesis, and plant-pathogen interaction. On this basis, we sequenced the microbial diversity of the H and M leaves. The sequencing results suggested that the abundance of Didymella in the M leaves was significantly higher than that in the H leaves, which meant that M leaves might be infected by Didymella. CONCLUSIONS: Therefore, we speculated that Didymella infected M leaves while reduced Chl and carotenoid content by damaging chloroplast structures, and altered the intensity of photosynthesis, thereby causing the leaf yellowing phenomenon of C. japonica (M). This research will provide new insights into the leaf color variation mechanism and lay a theoretical foundation for plant breeding and molecular markers.


Assuntos
Camellia/anatomia & histologia , Camellia/genética , Camellia/metabolismo , Cor , Microbiota , Folhas de Planta/anatomia & histologia , Folhas de Planta/metabolismo , Carotenoides/metabolismo , China , Clorofila/metabolismo , Produtos Agrícolas/anatomia & histologia , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Variação Genética , Genótipo , Fenótipo , Transcriptoma
6.
Molecules ; 26(17)2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34500767

RESUMO

Chitosan (CTS) is a deacetylated derivative of chitin that is involved in adaptive response to abiotic stresses. However, the regulatory role of CTS in heat tolerance is still not fully understood in plants, especially in grass species. The aim of this study was to investigate whether the CTS could reduce heat-induced senescence and damage to creeping bentgrass associated with alterations in antioxidant defense, chlorophyll (Chl) metabolism, and the heat shock pathway. Plants were pretreated exogenously with or without CTS (0.1 g L-1) before being exposed to normal (23/18 °C) or high-temperature (38/33 °C) conditions for 15 days. Heat stress induced detrimental effects, including declines in leaf relative water content and photochemical efficiency, but significantly increased reactive oxygen species (ROS) accumulation, membrane lipid peroxidation, and Chl loss in leaves. The exogenous application of CTS significantly alleviated heat-induced damage in creeping bentgrass leaves by ameliorating water balance, ROS scavenging, the maintenance of Chl metabolism, and photosynthesis. Compared to untreated plants under heat stress, CTS-treated creeping bentgrass exhibited a significantly higher transcription level of genes involved in Chl biosynthesis (AsPBGD and AsCHLH), as well as a lower expression level of Chl degradation-related gene (AsPPH) and senescence-associated genes (AsSAG12, AsSAG39, Asl20, and Ash36), thus reducing leaf senescence and enhancing photosynthetic performance under heat stress. In addition, the foliar application of CTS significantly improved antioxidant enzyme activities (SOD, CAT, POD, and APX), thereby effectively reducing heat-induced oxidative damage. Furthermore, heat tolerance regulated by the CTS in creeping bentgrass was also associated with the heat shock pathway, since AsHSFA-6a and AsHSP82 were significantly up-regulated by the CTS during heat stress. The potential mechanisms of CTS-regulated thermotolerance associated with other metabolic pathways still need to be further studied in grass species.


Assuntos
Agrostis/efeitos dos fármacos , Antioxidantes/farmacologia , Quitosana/farmacologia , Clorofila/metabolismo , Temperatura Alta , Folhas de Planta/efeitos dos fármacos , Agrostis/metabolismo , Resposta ao Choque Térmico/efeitos dos fármacos , Folhas de Planta/metabolismo
7.
PLoS One ; 16(9): e0257745, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34570827

RESUMO

In recent years, much effort has been devoted to understanding the response of plants to various light sources, largely due to advances in industry light-emitting diodes (LEDs). In this study, the effect of different light modes on rocket (Eruca sativa. Mill.) photosynthetic performance and other physiological traits was evaluated using an orthogonal design based on a combination between light intensity, quality, and photoperiod factors. Some morphological and biochemical parameters and photosynthetic efficiency of the plants were analyzed. Plants grew in a closed chamber where three light intensities (160, 190, and 220 µmol m-2 s-1) provided by LEDs with a combination of different ratios of red, green, and blue (R:G:B- 7:0:3, 3:0:7, and 5:2:3) and three different photoperiods (light/dark -10/14 h, 12/12 h, and 14/10 h) were used and compared with white fluorescent light (control). This experimental setup allowed us to study the effect of 9 light modes (LM) compared to white light. The analyzes performed showed that the highest levels of chlorophyll a, chlorophyll b, and carotenoids occurred under LM4, LM3, and LM1, respectively. Chlorophyll a fluorescence measurement showed that the best effective quantum yield of PSII photochemistry Y(II), non-photochemical quenching (NPQ), photochemical quenching coefficient (qP), and electron transport ratio (ETR) were obtained under LM2. The data showed that the application of R7:G0:B3 light mode with a shorter photoperiod than 14/10 h (light/dark), regardless of the light intensity used, resulted in a significant increase in growth as well as higher photosynthetic capacity of rocket plants. Since, a clear correlation between the studied traits under the applied light modes was not found, more features should be studied in future experiments.


Assuntos
Brassicaceae/fisiologia , Fotossíntese , Brassicaceae/crescimento & desenvolvimento , Carotenoides/metabolismo , Clorofila/metabolismo , Luz , Fotoperíodo
8.
BMC Plant Biol ; 21(1): 438, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34583634

RESUMO

BACKGROUND: Chlorophyll (Chl) is a vital photosynthetic pigment involved in capturing light energy and energy conversion. In this study, the color conversion of inner-leaves from green to yellow in the new wucai (Brassica campestris L.) cultivar W7-2 was detected under low temperature. The W7-2 displayed a normal green leaf phenotype at the seedling stage, but the inner leaves gradually turned yellow when the temperature was decreased to 10 °C/2 °C (day/night), This study facilitates us to understand the physiological and molecular mechanisms underlying leaf color changes in response to low temperature. RESULTS: A comparative leaf transcriptome analysis of W7-2 under low temperature treatment was performed on three stages (before, during and after leaf color change) with leaves that did not change color under normal temperature at the same period as a control. A total of 67,826 differentially expressed genes (DEGs) were identified. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) analysis revealed that the DEGs were mainly enriched in porphyrin and Chl metabolism, carotenoids metabolism, photosynthesis, and circadian rhythm. In the porphyrin and chlorophyll metabolic pathways, the expression of several genes was reduced [i.e. magnesium chelatase subunit H (CHLH)] under low temperature. Almost all genes [i.e. phytoene synthase (PSY)] in the carotenoids (Car) biosynthesis pathway were downregulated under low temperature. The genes associated with photosynthesis [i.e. photosystem II oxygen-evolving enhancer protein 1 (PsbO)] were also downregulated under LT. Our study also showed that elongated hypocotyl5 (HY5), which participates in circadian rhythm, and the metabolism of Chl and Car, is responsible for the regulation of leaf color change and cold tolerance in W7-2. CONCLUSIONS: The color of inner-leaves was changed from green to yellow under low temperature in temperature-sensitive mutant W7-2. Physiological, biochemical and transcriptomic studies showed that HY5 transcription factor and the downstream genes such as CHLH and PSY, which regulate the accumulation of different pigments, are required for the modulation of leaf color change in wucai under low temperature.


Assuntos
Brassica/genética , Brassica/metabolismo , Clorofila/metabolismo , Resposta ao Choque Frio/fisiologia , Pigmentação/genética , Pigmentação/fisiologia , Folhas de Planta/metabolismo , Clorofila/genética , Regulação da Expressão Gênica de Plantas , Transcriptoma
9.
PLoS One ; 16(9): e0257023, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34555032

RESUMO

Abiotic stress, especially a lack of water, can significantly reduce crop yields. In this study, we evaluated the physiological and biochemical effects of potassium sulfate (K2SO4) fertilizer and varied irrigation regimes on the economically significant oilseed crop, Brassica juncea L, under open field conditions. Two cultivars (RH-725 and RH-749) of B. juncea were used in a randomized complete block design experiment with three replicates. Irrigation regimes consisted of a control (double irrigation: once at the 50% flowering and another at 50% fruiting stages), early irrigation (at 50% flowering only), late irrigation (at 50% fruiting only) and stress (no irrigation). The K2SO4 applications were: control (K0, no fertilization); K1, 10 kg ha-1; and K2, 20 kg ha-1. We measured growth via fresh and dry plant weight, plant height, root length, and leaf area. All the growth parameters were higher in RH-749. The physiological attributes, including the membrane stability index and relative water content, were higher at the 50% flowering stage in RH-749. The amount of antioxidant enzymes (catalase (CAT), guaiacol peroxidase (POX), ascorbate peroxidase (APX), and superoxide dismutase (SOD)) was enhanced when both plants were fertilized during water stress. All of these enzymes had higher activity in RH-749. The total chlorophyll content and photosynthesis rate were considerably higher in RH-749, which leaked fewer electrolytes and maintained a less destructive osmotic potential under limited water conditions. The results indicated that it is water-stress tolerant when given a high concentration of K2SO4, which alleviated the adverse effects of water stress on growth and physiology.


Assuntos
Irrigação Agrícola/métodos , Fertilizantes/análise , Mostardeira/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos , Sulfatos/farmacologia , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Secas , Flores/efeitos dos fármacos , Flores/crescimento & desenvolvimento , Flores/metabolismo , Frutas/efeitos dos fármacos , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Mostardeira/crescimento & desenvolvimento , Mostardeira/metabolismo , Peroxidase/metabolismo , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Especificidade da Espécie , Estresse Fisiológico/fisiologia , Superóxido Dismutase/metabolismo , Água/metabolismo
10.
Int J Mol Sci ; 22(17)2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34502258

RESUMO

Magnetopriming has emerged as a promising seed-priming method, improving seed vigor, plant performance and productivity under both normal and stressed conditions. Various recent reports have demonstrated that improved photosynthesis can lead to higher biomass accumulation and overall crop yield. The major focus of the present review is magnetopriming-based, improved growth parameters, which ultimately favor increased photosynthetic performance. The plants originating from magnetoprimed seeds showed increased plant height, leaf area, fresh weight, thick midrib and minor veins. Similarly, chlorophyll and carotenoid contents, efficiency of PSII, quantum yield of electron transport, stomatal conductance, and activities of carbonic anhydrase (CA), Rubisco and PEP-carboxylase enzymes are enhanced with magnetopriming of the seeds. In addition, a higher fluorescence yield at the J-I-P phase in polyphasic chlorophyll a fluorescence (OJIP) transient curves was observed in plants originating from magnetoprimed seeds. Here, we have presented an overview of available studies supporting the magnetopriming-based improvement of various parameters determining the photosynthetic performance of crop plants, which consequently increases crop yield. Additionally, we suggest the need for more in-depth molecular analysis in the future to shed light upon hidden regulatory mechanisms involved in magnetopriming-based, improved photosynthetic performance.


Assuntos
Campos Magnéticos , Fotossíntese , Proteínas de Plantas/metabolismo , Plantas/metabolismo , Clorofila/química , Clorofila/metabolismo , Fluorescência , Folhas de Planta/metabolismo , Sementes/crescimento & desenvolvimento , Sementes/metabolismo
11.
Environ Toxicol Pharmacol ; 88: 103746, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34536620

RESUMO

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a popular group of drugs used worldwide. These drugs are also available over the counter, which implies that their consumption is not strictly regulated. They are released through wastewater and feces and can have adverse effects on the environment. The present study aimed to evaluate the effect of two NSAIDs, diclofenac (DCF) and naproxen (NAP), and their mixture (DCF + NAP) on spring barley seedlings and ostracods Heterocypris incongruens. The tested drugs had a negative impact on bivalve ostracods and the studied plants. DCF was the most toxic toward ostracods, while spring barley seedlings were affected the most by NAP. The application of the tested compounds and their mixture resulted in a decrease in fresh weight yield and the content of photosynthetic pigments. In addition, an increase in H2O2 and proline content and changes in the activity of antioxidant enzymes (POD, APX, CAT, and SOD) were observed.


Assuntos
Anti-Inflamatórios não Esteroides/toxicidade , Crustáceos/efeitos dos fármacos , Diclofenaco/toxicidade , Hordeum/efeitos dos fármacos , Naproxeno/toxicidade , Plântula/efeitos dos fármacos , Animais , Carotenoides/metabolismo , Clorofila/metabolismo , Crustáceos/crescimento & desenvolvimento , Interações Medicamentosas , Hordeum/crescimento & desenvolvimento , Hordeum/metabolismo , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Oxirredutases/metabolismo , Proteínas de Plantas/metabolismo , Prolina/metabolismo , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
12.
Nat Commun ; 12(1): 4866, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34381045

RESUMO

Plants invest a considerable amount of leaf nitrogen in the photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO), forming a strong coupling of nitrogen and photosynthetic capacity. Variability in the nitrogen-photosynthesis relationship indicates different nitrogen use strategies of plants (i.e., the fraction nitrogen allocated to RuBisCO; fLNR), however, the reason for this remains unclear as widely different nitrogen use strategies are adopted in photosynthesis models. Here, we use a comprehensive database of in situ observations, a remote sensing product of leaf chlorophyll and ancillary climate and soil data, to examine the global distribution in fLNR using a random forest model. We find global fLNR is 18.2 ± 6.2%, with its variation largely driven by negative dependence on leaf mass per area and positive dependence on leaf phosphorus. Some climate and soil factors (i.e., light, atmospheric dryness, soil pH, and sand) have considerable positive influences on fLNR regionally. This study provides insight into the nitrogen-photosynthesis relationship of plants globally and an improved understanding of the global distribution of photosynthetic potential.


Assuntos
Nitrogênio/metabolismo , Fotossíntese , Folhas de Planta/metabolismo , Clorofila/metabolismo , Clima , Ecossistema , Internacionalidade , Modelos Teóricos , Fósforo/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Solo/química
13.
BMC Plant Biol ; 21(1): 377, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34399687

RESUMO

BACKGROUND: C. panzhihuaensis is more tolerant to freezing than C. bifida but the mechanisms underlying the different freezing tolerance are unclear. Photosynthesis is one of the most temperature-sensitive processes. Lipids play important roles in membrane structure, signal transduction and energy storage, which are closely related to the stress responses of plants. In this study, the chlorophyll fluorescence parameters and lipid profiles of the two species were characterized to explore the changes in photosynthetic activity and lipid metabolism following low-temperature exposure and subsequent recovery. RESULTS: Photosynthetic activity significantly decreased in C. bifida with the decrease of temperatures and reached zero after recovery. Photosynthetic activity, however, was little affected in C. panzhihuaensis. The lipid composition of C. bifida was more affected by cold and freezing treatments than C. panzhihuaensis. Compared with the control, the proportions of all the lipid categories recovered to the original level in C. panzhihuaensis, but the proportions of most lipid categories changed significantly in C. bifida after 3 d of recovery. In particular, the glycerophospholipids and prenol lipids degraded severely during the recovery period of C. bifida. Changes in acyl chain length and double bond index (DBI) occurred in more lipid classes immediately after low-temperature exposure in C. panzhihuaensis compare with those in C. bifida. DBI of the total main membrane lipids of C. panzhihuaensis was significantly higher than that of C. bifida following all temperature treatments. CONCLUSIONS: The results of chlorophyll fluorescence parameters confirmed that the freezing tolerance of C. panzhihuaensis was greater than that of C. bifida. The lipid metabolism of the two species had differential responses to low temperatures. The homeostasis and plastic adjustment of lipid metabolism and the higher level of DBI of the main membrane lipids may contribute to the greater tolerance of C. panzhihuaensis to low temperatures.


Assuntos
Aclimatação , Cycas/fisiologia , Lipídeos de Membrana/metabolismo , China , Clorofila/metabolismo , Cycas/metabolismo , Congelamento , Glicerofosfatos/metabolismo , Homeostase , Especificidade da Espécie , Temperatura
14.
BMC Plant Biol ; 21(1): 368, 2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34384391

RESUMO

BACKGROUND: Melatonin is considered a potential plant growth regulator to enhance the growth of plants and increase tolerance to various abiotic stresses. Nevertheless, melatonin's role in mediating stress response in different plant species and growth cycles still needs to be explored. This study was conducted to understand the impact of different melatonin concentrations (0, 50, 100, and 150 µM) applied as a soil drench to maize seedling under drought stress conditions. A decreased irrigation approach based on watering was exposed to maize seedling after drought stress was applied at 40-45% of field capacity. RESULTS: The results showed that drought stress negatively affected the growth behavior of maize seedlings, such as reduced biomass accumulation, decreased photosynthetic pigments, and enhanced the malondialdehyde and reactive oxygen species (ROS). However, melatonin application enhanced plant growth; alleviated ROS-induced oxidative damages by increasing the photosynthetic pigments, antioxidant enzyme activities, relative water content, and osmo-protectants of maize seedlings. CONCLUSIONS: Melatonin treatment also enhanced the stomatal traits, such as stomatal length, width, area, and the number of pores under drought stress conditions. Our data suggested that 100 µM melatonin application as soil drenching could provide a valuable foundation for improving plant tolerance to drought stress conditions.


Assuntos
Melatonina/farmacologia , Reguladores de Crescimento de Plantas/farmacologia , Zea mays/efeitos dos fármacos , Zea mays/crescimento & desenvolvimento , Antioxidantes/metabolismo , Biomassa , Clorofila/metabolismo , Secas , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/ultraestrutura , Proteínas de Plantas/metabolismo , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/ultraestrutura , Prolina/metabolismo , Espécies Reativas de Oxigênio , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Açúcares/metabolismo , Zea mays/enzimologia , Zea mays/fisiologia
15.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445145

RESUMO

The main goal of growing plants under various photoperiods is to optimize photosynthesis for using the effect of day length that often acts on plants in combination with biotic and/or abiotic stresses. In this study, Brassica juncea plants were grown under four different day-length regimes, namely., 8 h day/16 h night, 12 h day/12 h night, 16 h day/8 h night, and continuous light, and were infected with a necrotrophic fungus Alternaria brassicicola. The development of necroses on B. juncea leaves was strongly influenced by leaf position and day length. The largest necroses were formed on plants grown under a 16 h day/8 h night photoperiod at 72 h post-inoculation (hpi). The implemented day-length regimes had a great impact on leaf morphology in response to A. brassicicola infection. They also influenced the chlorophyll and carotenoid contents and photosynthesis efficiency. Both the 1st (the oldest) and 3rd infected leaves showed significantly higher minimal fluorescence (F0) compared to the control leaves. Significantly lower values of other investigated chlorophyll a fluorescence parameters, e.g., maximum quantum yield of photosystem II (Fv/Fm) and non-photochemical quenching (NPQ), were observed in both infected leaves compared to the control, especially at 72 hpi. The oldest infected leaf, of approximately 30% of the B. juncea plants, grown under long-day and continuous light conditions showed a 'green island' phenotype in the form of a green ring surrounding an area of necrosis at 48 hpi. This phenomenon was also reflected in changes in the chloroplast's ultrastructure and accelerated senescence (yellowing) in the form of expanding chlorosis. Further research should investigate the mechanism and physiological aspects of 'green islands' formation in this pathosystem.


Assuntos
Alternaria/patogenicidade , Mostardeira/microbiologia , Mostardeira/fisiologia , Necrose/microbiologia , Necrose/patologia , Fotossíntese/fisiologia , Doenças das Plantas/microbiologia , Carotenoides/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Fluorescência , Mostardeira/metabolismo , Necrose/metabolismo , Fotoperíodo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia
16.
Biomolecules ; 11(8)2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34439809

RESUMO

Leaf senescence, the last stage of leaf development, is a well-regulated and complex process for investigation. For simplification, dark-induced leaf senescence has frequently been used to mimic the natural senescence of leaves because many typical senescence symptoms, such as chlorophyll (Chl) and protein degradation, also occur under darkness. In this study, we compared the phenotypes of leaf senescence that occurred when detached leaves or intact plants were incubated in darkness to induce senescence. We found that the symptoms of non-programmed cell death (non-PCD) with remaining green coloration occurred more heavily in the senescent leaves of whole plants than in the detached leaves. The pheophorbide a (Pheide a) content was also shown to be much higher in senescent leaves when whole plants were incubated in darkness by analyses of leaf Chl and its metabolic intermediates. In addition, more serious non-PCD occurred and more Pheide a accumulated in senescent leaves during dark incubation if the soil used for plant growth contained more water. Under similar conditions, the non-PCD phenotype was alleviated and the accumulation of Pheide a was reduced by overexpressing 7-hydroxymethyl Chl a (HMChl a) reductase (HCAR). Taken together, we conclude that a high soil water content induced non-PCD by decreasing HCAR activity when whole plants were incubated in darkness to induce senescence; thus, the investigation of the fundamental aspects of biochemistry and the regulation of leaf senescence are affected by using dark-induced leaf senescence.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Clorofila/análogos & derivados , Regulação da Expressão Gênica de Plantas , Oxirredutases/genética , Folhas de Planta/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Morte Celular , Clorofila/metabolismo , Escuridão , Oxirredutases/metabolismo , Fenótipo , Fotossíntese/genética , Células Vegetais/metabolismo , Folhas de Planta/metabolismo , Estabilidade Proteica , Proteólise , Solo/química , Água/metabolismo
17.
Int J Mol Sci ; 22(15)2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34360743

RESUMO

Under natural environments, light quality and quantity are extremely varied. To respond and acclimate to such changes, plants have developed a multiplicity of molecular regulatory mechanisms. Non-photochemical quenching of chlorophyll fluorescence (NPQ) and thylakoid protein phosphorylation are two mechanisms that protect vascular plants. To clarify the role of thylakoid protein phosphorylation in energy-dependent quenching of chlorophyll fluorescence (qE) in rice plants, we used a direct Western blot assay after BN-PAGE to detect all phosphoproteins by P-Thr antibody as well as by P-Lhcb1 and P-Lhcb2 antibodies. Isolated thylakoids in either the dark- or the light-adapted state from wild type (WT) and PsbS-KO rice plants were used for this approach to detect light-dependent interactions between PsbS, PSII, and LHCII proteins. We observed that the bands corresponding to the phosphorylated Lhcb1 and Lhcb2 as well as the other phosphorylated proteins were enhanced in the PsbS-KO mutant after illumination. The qE relaxation became slower in WT plants after 10 min HL treatment, which correlated with Lhcb1 and Lhcb2 protein phosphorylation in the LHCII trimers under the same experimental conditions. Thus, we concluded that light-induced phosphorylation of PSII core and Lhcb1/Lhcb2 proteins is enhanced in rice PsbS-KO plants which might be due to more reactive-oxygen-species production in this mutant.


Assuntos
Clorofila/metabolismo , Fluorescência , Complexos de Proteínas Captadores de Luz/metabolismo , Luz , Oryza/metabolismo , Tilacoides/metabolismo , Clorofila/genética , Complexos de Proteínas Captadores de Luz/genética , Oryza/genética , Fosforilação , Complexo de Proteína do Fotossistema II/genética , Complexo de Proteína do Fotossistema II/metabolismo , Tilacoides/genética
18.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34445687

RESUMO

Leaf coloration changes evoke different photosynthetic responses among different poplar cultivars. The aim of this study is to investigate the photosynthetic difference between a red leaf cultivar (ZHP) and a green leaf (L2025) cultivar of Populus deltoides. In this study, 'ZHP' exhibited wide ranges and huge potential for absorption and utilization of light energy and CO2 concentration which were similar to those in 'L2025' and even showed a stronger absorption for weak light. However, with the increasing light intensity and CO2 concentration, the photosynthetic capacity in both 'L2025' and 'ZHP' was gradually restricted, and the net photosynthetic rate (Pn) in 'ZHP' was significantly lower than that in 'L2025'under high light or high CO2 conditions, which was mainly attributed to stomatal regulation and different photosynthetic efficiency (including the light energy utilization efficiency and photosynthetic CO2 assimilation efficiency) in these two poplars. Moreover, the higher anthocyanin content in 'ZHP' than that in 'L2025' was considered to be closely related to the decreased photosynthetic efficiency in 'ZHP'. According to the results from the JIP-test, the capture efficiency of the reaction center for light energy in 'L2025' was significantly higher than that in 'ZHP'. Interestingly, the higher levels of light quantum caused relatively higher accumulation of QA- in 'L2025', which blocked the electron transport and weakened the photosystem II (PSII) performance as compared with 'ZHP'; however, the decreased capture of light quantum also could not promote the utilization of light energy, which was the key to the low photosynthetic efficiency in 'ZHP'. The differential expressions of a series of photosynthesis-related genes further promoted these specific photosynthetic processes between 'L2025' and 'ZHP'.


Assuntos
Fotossíntese/fisiologia , Folhas de Planta/fisiologia , Populus/fisiologia , Dióxido de Carbono/metabolismo , Clorofila/metabolismo , Cor , Transporte de Elétrons/fisiologia , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Populus/genética , Populus/metabolismo
19.
Sci Rep ; 11(1): 16651, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404821

RESUMO

A 2-year field experiment was conducted to analyze the growth conditions, physical features, yield, and nitrogen use efficiency (NUE) of sugar-beet under limited irrigation conditions in northeast of China. A cultivar H003 was used as plant materials; six treatments (C1-C6) were included: C1, no nitrogen applied, rain-fed; C2, nitrogen (120.00 kg ha-1), rain-fed; C3, no nitrogen applied, hole irrigation for seeding; C4, nitrogen (120.00 kg ha-1), hole irrigation for seeding; C5, no nitrogen applied, hole irrigation for seeding; and C6, nitrogen (120.00 kg ha-1), hole irrigation for seeding, and irrigation at foliage rapid growth stage. The irrigation supply was only 500 mL/plant once. Results showed C6 showed the highest chlorophyll content, dry matter accumulation, yield, etc. and had the best NUE among all the treatments. In conclusion, under the routine fertilization conditions of northeast of China, the cultivation measure of hole irrigation 500 mL/plant for seeding combined with irrigation 500 mL/plant at foliage rapid growth stage greatly improved sugar-beet yield and NUE.


Assuntos
Irrigação Agrícola , Beta vulgaris/crescimento & desenvolvimento , Clorofila/metabolismo , Nitrogênio/metabolismo , Beta vulgaris/metabolismo , Biomassa , China , Fertilizantes/análise
20.
Sci Rep ; 11(1): 15736, 2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34344961

RESUMO

Global warming has significantly altered the distribution and productivity of vegetation owing to shifts in plant functional traits. However, chlorophyll adaptations-good representative of plant production-in grasslands have not been investigated on a large scale, hindering ecological predictions of climate change. Three grassland transects with a natural temperature gradient were designed in the Tibetan, Mongolian, and Loess Plateau to describe the changes in chlorophyll under different warming scenarios for 475 species. In the three plateaus, variations and distributions of species chlorophyll concentration and composition were compared. The results showed that the means of chlorophyll concentration and composition (chlorophyll a/b) increased with the mean annual temperature. Still, their distributions shifted in opposite manners: chlorophyll concentration was distributed in a broader but more differential manner, while chlorophyll composition was distributed in a narrower but more uniform manner. Compared to chlorophyll concentration, chlorophyll composition was more conservative, with a slight shift in distribution. At the regional level, the chlorophyll concentration and composition depend on the limitations of the local climate or resources. The results implied that warming might drive shifts in grassland chlorophyll distribution mainly by alternations in species composition. Large-scale chlorophyll investigations will be useful for developing prediction techniques.


Assuntos
Clorofila/química , Clorofila/metabolismo , Aquecimento Global , Pradaria , Estações do Ano , Temperatura , Monitoramento Ambiental
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