Prediction of soil seed bank of piedmont and alluvial environments of Dera Ghazi Khan, Punjab, Pakistan / Predição do banco de sementes do solo do piemonte e ambientes aluviais de Dera Ghazi Khan, Punjab, Paquistão

Abstract The current focus is on the overall pattern of seed storage present in the fragments of the soil of piedmont and alluvial landscapes of the environment. The present study predicted the seed banks of both soils of alluvial and piedmont zones in different ecological conditions and evaluate the potential of seeds in the restoration of both environments. The composition of the seed bank of soil is mainly affected by the alluvial environment and the structure of cleared area shows that more species of germinating annual grasses and growable seeds with the higher total number. Extant vegetation structures have an important role in the diversity of soil seed reservoirs, whose composition corresponded with the openness of the site. When in situ soil seed bank is recruited, it helps to restore only some components of the plant community in an alluvial environment. In our current research, it was confirmed that seed richness was higher in number at lower elevation (alluvial) than that at high elevation (piedmont). Seed richness showed a significant negative correlation with anions, cations, while significantly positive with altitude that suggests the richness pattern of the overall seed bank of the area is influenced by various environmental factors.

Resumo O foco atual está no padrão geral de armazenamento de sementes presente nos fragmentos de solo do Piemonte e nas paisagens aluviais do meio ambiente. O presente estudo previu os bancos de sementes de ambos os solos das zonas aluvial e piemontesa em diferentes condições ecológicas e avaliou o potencial das sementes na restauração de ambos os ambientes. A composição do banco de sementes do solo é afetada principalmente pelo ambiente aluvial e a estrutura da área desmatada mostra que mais espécies de gramíneas anuais em germinação e sementes cultiváveis ​​apresentam o maior número total. As estruturas da vegetação existente têm um papel importante na diversidade dos reservatórios de sementes do solo, cuja composição correspondeu à abertura do local. Quando o banco de sementes do solo in situ é recrutado, o mesmo ajuda a restaurar apenas alguns componentes da comunidade de plantas em um ambiente aluvial. Em nossa pesquisa atual, foi confirmado que a riqueza de sementes era maior em número em altitudes mais baixas (aluviais) do que em altitudes elevadas (Piemonte). A riqueza de sementes mostrou uma correlação negativa significativa com ânions, cátions, enquanto significativamente positiva com a altitude, o que sugere que o padrão de riqueza do banco geral de sementes da área é influenciado por vários fatores ambientais.

What triggers phenological events in plants under seasonal environments? A study with phylogenetically related plant species in sympatry / O que desencadeia eventos fenológicos em plantas em ambientes sazonais? Um estudo com espécies de plantas filogeneticamente relacionadas e em simpatria

In this study, we evaluated variation in vegetative and reproductive phenological events of four phylogenetically related plant species subjected to a seasonal environment. To this aim, we sampled 15 individuals of each plant species every fortnight for one year, between January and December of 2017. To assess when a given phenophase occurred more intensely in the population, the Fournier intensity index was used and the synchrony of individuals of the sample in a given phenological event was estimated using the activity index. The Rayleigh (Z) test was used to determine whether the phenological events have seasonal distribution. The relationship of abiotic factors (photoperiod, precipitation, relative humidity and temperature) with the intensity of phenophases was evaluated for each plant species using generalized linear models (GLMs). The phenophases of all plants showed a seasonal distribution pattern, as well as variation in synchrony of phenophases and specific sets of abiotic factors significantly influenced their phenophases. New leaves, for example, were produced throughout the seasons, with intense leaf fall in the dry season. Flowering periods, on the other hand, did not overlap. Indeed, species exhibited sequential flowering and asynchronous flowering among individuals. Our results suggest that the phenological patterns of four sympatric plant species are directly linked to climatic variables, but different abiotic factors affected different phenophases.

Neste estudo, avaliamos a variação nos eventos fenológicos vegetativos e reprodutivos de quatro espécies de plantas filogeneticamente relacionadas submetidas a um ambiente sazonal. Para isso, amostramos 15 indivíduos de cada espécie quinzenalmente, pelo período de um ano, entre janeiro e dezembro de 2017. Para avaliar quando uma determinada fenofase ocorreu de modo mais intenso na população foi utilizado o índice de intensidade de Fournier e a sincronia dos indivíduos da amostra em determinado evento fenológico foi estimada utilizando-se o índice de atividade. O teste de Rayleigh (Z) foi usado para determinar se os eventos fenológicos têm distribuição sazonal. A relação dos fatores abióticos (fotoperíodo, precipitação, temperatura e umidade relativa) com a intensidade das fenofases foi avaliada para cada espécie de planta usando modelos lineares generalizados (GLMs). As fenofases de todas as plantas apresentaram um padrão de distribuição sazonal, bem como variação na sincronia das fenofases e conjuntos específicos de fatores abióticos influenciaram significativamente suas fenofases. Folhas novas, por exemplo, foram produzidas ao longo das estações, com intensa queda de folhas na estação seca. Os períodos de floração, por outro lado, não se sobrepuseram. De fato, as espécies exibiram floração sequencial e floração assíncrona entre os indivíduos. Nossos resultados sugerem que os padrões fenológicos das quatro espécies de plantas simpátricas estão diretamente ligados às variáveis climáticas, mas diferentes fatores abióticos afetaram diferentes fenofases.

Cadmium toxicity symptoms and uptake mechanism in plants: a review / Sintomas de toxicidade de cádmio e mecanismo de absorção em plantas: uma revisão

Cadmium (Cd) is one of non-essential heavy metals which is released into environment naturally or anthropogenically. It is highly persistent toxic metals that are exceptionally distressing industrial and agriculture activities by contaminating soil, water and food. Its long-duration endurance in soil and water results in accumulation and uptake into plants, leading to the food chain. This becomes a serious global problem threatening humans and animals as food chain components. Living organisms, especially humans, are exposed to Cd through plants as one of the main vegetative food sources. This review paper is concentrated on the symptoms of the plants affected by Cd toxicity. The absorption of Cd triggers several seen and unseen symptoms by polluted plants such as stunted growth, chlorosis, necrosis and wilting. Apart from that, factors that affect the uptake and translocation of Cd in plants are elaborated to understand the mechanism that contributes to its accumulation. By insight of Cd accumulation, this review also discussed the phytoremediation techniques-phytoextraction, phytostimulation, phytostabilization, phytovolatization and rhizofiltration in bioremediating the Cd.

O cádmio (Cd) é um dos metais pesados ​​não essenciais que é liberado no meio ambiente de forma natural ou antropogênica. São metais tóxicos altamente persistentes que prejudicam excepcionalmente as atividades industriais e agrícolas, contaminando o solo, a água e os alimentos. Sua resistência de longa duração no solo e na água resulta em acúmulo e absorção pelas plantas, levando à cadeia alimentar. Isso se torna um sério problema global que ameaça humanos e animais como componentes da cadeia alimentar. Os organismos vivos, principalmente os humanos, são expostos ao Cd através das plantas como uma das principais fontes de alimento vegetativo. Este artigo de revisão concentra-se nos sintomas das plantas afetadas pela toxicidade do Cd. A absorção de Cd desencadeia vários sintomas visíveis e invisíveis por plantas poluídas, como crescimento atrofiado, clorose, necrose e murcha. Além disso, são elaborados fatores que afetam a absorção e translocação de Cd nas plantas para entender o mecanismo que contribui para o seu acúmulo. A partir do conhecimento do acúmulo de Cd, esta revisão também discutiu as técnicas de fitorremediação - fitoextração, fitoestimulação, fitoestabilização, fitovolatização e rizofiltração na biorremediação do Cd.

Light-Dependent Control of Metabolism in Plants.

The energy of sunlight is converted into chemical energy during photosynthesis in plants [...].

Plant-pathogen interactions: The need to evolve to stay the same.

Plants and microorganisms have a long-standing relationship involving mutual and continuous adaptations. A new study shows that several molecular tools plants use to recognize their pathogens were already present when plants colonized the land.

Study on the performance of vertical flow constructed wetland microcosm with Canna sps. for treatment of high chromium-containing wastewater.

Chromium (Cr (VI)) pollution has plagued the environment due to chromite mining and various industrial actions. Constructed wetlands (CW) have emerged as a potential wastewater management technique that utilizes physical, chemical, and biological processes. The present study investigates the use of vertical flow-constructed wetlands (CW) using manure-rich garden soil and sand as substrates in planted CW (CW-P) and unplanted CW (CW-UP) to remove Cr (VI) from simulated wastewater. The experiment was performed in two phases, i.e., Phase I and II, in the same system. In Phase I, initial Cr (VI) concentrations were varied between 5 and 200 mg/l at a fixed hydraulic retention time (HRT) of 48 h, while in Phase II, the effect of HRT (24 h, 48 h, and 96 h) was studied at a fixed Cr (VI) concentration of 200 mg/L in the influent. At 24 h, HRT removal efficiencies were 90.20% for CW-P and 86.41% for CW-UP. However, at 96 h of HRT, the system showed nearly the same removal efficiency. Scanning electron microscopy with energy dispersion X-Ray spectroscopy analysis suggested the conversion of Cr (VI) to Cr (III) in soil precipitate and the translocation of Cr (VI) in plant tissues (Canna sps.). Moreover, microbial diversity profiling indicated that microbial diversity involved in pollutant removal differed in both systems. The phytotoxicity test clearly showed the decrease in toxicity level in the treated effluent, concluding the reusability of treated water. This exploratory study suggested that the CW can potentially remove a higher concentration of hexavalent chromium at longer HRT.

Cadmium Exposure and Cardiovascular Diseases.

Cadmium lurks in our food, water, and air silently wreaking havoc on human health. It accumulates in plants and mammals, lasting 25-30 years. Herein, we highlight the potential link between cadmium exposure and cardiovascular disorders in humans.

Detection of Sugarcane bacilliform virus in diseased sugarcane plants in Andhra Pradesh, India by serological and molecular methods.

Sugarcane leaf fleck incited by Sugarcane bacilliform virus is emerging as a major disease and affecting exchange of sugarcane germplasm and cultivation worldwide. Roving surveys conducted in 162 fields belonging to 81 villages spread over 14 sugarcane growing districts of Andhra Pradesh during 2021-2022 revealed 8 to 44% incidence of the disease. Mean maximum fleck disease incidence was reported in Anakapalli district (33.00%) followed by Srikakulam district (22.66%), whereas least incidence was observed in Alluri Sitharamaraju district (9.33%). The early and sensitive detection of pathogens is vital and necessary to reduce the danger of introducing new diseases or pathogen strains into sugarcane growing regions. Both serological and molecular methods were used in proposed investigation to identify the virus at the protein and nucleic acid levels. DAS-ELISA results were positive for 50 suspected SCBV infected sugarcane leaf samples out of 81, with mean absorbance (A405) values ranging from 0.50 to 2.20. Further PCR assays were performed using SCBV-specific primers targeting RT/RNase H coding region which is frequently employed as a taxonomic marker for species delineation in Badnaviruses. Out of 81 symptomatic samples collected, 61 samples gave positive results, and no amplification was observed in healthy control and negative control. Results made it evident that PCR was more sensitive than DAS-ELISA. Low virus concentration or variation in virus strains may be the reason for the low detection rate in DAS-ELISA in the current study. Extensive roving surveys conducted for the incidence of leaf fleck disease for the first time in the state of Andhra Pradesh revealed severe occurrence of leaf fleck disease under field conditions.

RIN enhances plant disease resistance via root exudate-mediated assembly of disease-suppressive rhizosphere microbiota.

The RIPENING-INHIBITOR (RIN) transcriptional factor is a key regulator governing fruit ripening. While RIN also affects other physiological processes, its potential roles in triggering interactions with the rhizosphere microbiome and plant health are unknown. Here we show that RIN affects microbiome-mediated disease resistance via root exudation, leading to recruitment of microbiota that suppress the soil-borne, phytopathogenic Ralstonia solanacearum bacterium. Compared with the wild-type (WT) plant, RIN mutants had different root exudate profiles, which were associated with distinct changes in microbiome composition and diversity. Specifically, the relative abundances of antibiosis-associated genes and pathogen-suppressing Actinobacteria (Streptomyces) were clearly lower in the rhizosphere of rin mutants. The composition, diversity, and suppressiveness of rin plant microbiomes could be restored by the application of 3-hydroxyflavone and riboflavin, which were exuded in much lower concentrations by the rin mutant. Interestingly, RIN-mediated effects on root exudates, Actinobacteria, and disease suppression were evident from the seedling stage, indicating that RIN plays a dual role in the early assembly of disease-suppressive microbiota and late fruit development. Collectively, our work suggests that, while plant disease resistance is a complex trait driven by interactions between the plant, rhizosphere microbiome, and the pathogen, it can be indirectly manipulated using "prebiotic" compounds that promote the recruitment of disease-suppressive microbiota.

Taking the lead: NLR immune receptor N-terminal domains execute plant immune responses.

Nucleotide-binding domain and leucine-rich repeat (NLR) proteins are important intracellular immune receptors that activate robust plant immune responses upon detecting pathogens. Canonical NLRs consist of a conserved tripartite architecture that includes a central regulatory nucleotide-binding domain, C-terminal leucine-rich repeats, and variable N-terminal domains that directly participate in immune execution. In flowering plants, the vast majority of NLR N-terminal domains belong to the coiled-coil, Resistance to Powdery Mildew 8, or Toll/interleukin-1 receptor subfamilies, with recent structural and biochemical studies providing detailed mechanistic insights into their functions. In this insight review, we focus on the immune-related biochemistries of known plant NLR N-terminal domains and discuss the evolutionary diversity of atypical NLR domains in nonflowering plants. We further contrast these observations against the known diversity of NLR-related receptors from microbes to metazoans across the tree of life.

Vv-circSIZ1 mediated by pre-mRNA processing machinery contributes to salt tolerance.

CircRNAs exist widely in plants, but the regulatory mechanisms for the biogenesis and function of plant circRNAs remain largely unknown. Using extensive mutagenesis of expression plasmids and genetic transformation methods, we analyzed the biogenesis and anti-salt functions of a new grape circRNA Vv-circSIZ1. We identified Vv-circSIZ1 that is mainly expressed in the cytoplasm of xylem. CircSIZ1 is species-specific, and genomic circSIZ1-forming region of seven tested species could be backspliced in Nicotiana benthamiana, but not in Arabidopsis. The retention length of Vv-circSIZ1 flanking introns was significantly positively correlated with its generation efficiency. The precise splicing of Vv-circSIZ1 does not depend on its mature exon sequence or internal intron sequences, but on the AG/GT splicing signal sites and branch site of the flanking introns. The spliceosome activity was inversely proportional to the expression level of Vv-circSIZ1. Furthermore, RNA-binding proteins can regulate the expression of Vv-circSIZ1. The overexpression of Vv-circSIZ1 improved salt tolerance of grape and N. benthamiana. Additionally, Vv-circSIZ1 could relieve the repressive effect of VvmiR3631 on its target VvVHAc1. Vv-circSIZ1 also promoted transcription of its parental gene. Overall, these results broaden our understanding of circRNAs in plants.

Mitigation of heavy metal stress in the soil through optimized interaction between plants and microbes.

Agricultural as well as industrial processes, such as mining and textile activities, are just a few examples of anthropogenic activities that have a long-term negative impact on the environment. Each of the aforementioned factors increases the concentration of heavy metals in soil. Heavy metal contamination in soil causes a wide range of environmental issues and is harmful to microbes, plants, and animals. Because of their non-biodegradability and toxic effects, preventing additional metal contamination and remediating the vast majority of contaminated sites around the world is critical. Hence, this review focuses on the effects of metal contamination on soil microbes, as well as plant-microbe interactions. Plant-associated probiotics reduce metal accumulation; the introduction of beneficial microbes is regarded as one of the most promising approaches to improving metal stress tolerance; thus, the study focuses on plant-microbe interactions as well as their actual implications via phytoremediation. Plant-microbe interaction can play an important role in acclimating vegetation (plants) to metalliferous conditions and should thus be studied to improve microbe-aided metal tolerance in plants. Plant-interacted microbes reduce metal accumulation in plant cells and metal bioaccumulation in the soil through a variety of processes. A novel phytobacterial approach, such as genetically modified microbes, is now being used to improve heavy metal cleanup as well as stress tolerance among plants. This review examines our current understanding of such negative consequences of heavy metal stresses, signaling responses, and the role of plant-associated microbiota in heavy metal stress tolerance and interaction.

Effect of stabilization time and soil chromium concentration on Sesbania virgata growth and metal tolerance.

Sesbania virgata is a pioneer shrub from the Fabaceae family, native to riparian environments in northeast of Argentina, southern of Brazil and Uruguay. In peri-urban riparian soils, metal contamination is a frequent problem, being its bioavailability partly determined by the stabilization time and frequency of contamination events. The effect of time elapsed between chromium (Cr) soil enrichment and plant seeding and Cr doses on S. virgata tolerance and metal absorption were evaluated. Treatments were developed by adding Cr (80-400 ppm) to the soil and allowing two days or fifteen months to elapse before sowing, and a control treatment without Cr addition. After 150 days from seeding, bioaccumulation and translocation factors, growth parameters (dry biomass and its aerial/radical allocation pattern, stem length and its elongation rate), morphological parameters (root volume and leaf area), and physiological parameters (chlorophyll content) of the specimens were determined. The emergence of S. virgata was inhibited since 150 ppm when Cr was added to the soil two days before seeding, with Cr accumulation in roots starting at 80 ppm (17.4 ± 2.5 mg kg-1). Under 15 months of metal stabilization, S. virgata plants survived across the entire range of Cr doses tested, with accumulation in roots since 100 ppm (35.5 ± 0.2 mg kg-1) and metal translocation to aerial tissues only under 400 ppm. The results obtained showed that S. virgata did not have high BCF and TF values, suggesting that it cannot be classified as bioaccumulator of Cr under the tested conditions. However, its presence in environments contaminated with Cr can be beneficial, as it helps to stabilize the metal in the soil.

Global seed dormancy patterns are driven by macroclimate but not fire regime.

Seed dormancy maximizes plant recruitment in habitats with variation in environmental suitability for seedling establishment. Yet, we still lack a comprehensive synthesis of the macroecological drivers of nondormancy and the different classes of seed dormancy: physiological dormancy, morphophysiological dormancy and physical dormancy. We examined current geographic patterns and environmental correlates of global seed dormancy variation. Combining the most updated data set on seed dormancy classes for > 10 000 species with > 4 million georeferenced species occurrences covering all of the world's biomes, we test how this distribution is driven by climate and fire regime. Seed dormancy is prevalent in seasonally cold and dry climates. Physiological dormancy occurs in relatively dry climates with high temperature seasonality (e.g. temperate grasslands). Morphophysiological dormancy is more common in forest-dominated, cold biomes with comparatively high and evenly distributed precipitation. Physical dormancy is associated with dry climates with strong seasonal temperature and precipitation fluctuations (e.g. deserts and savannas). Nondormancy is associated with stable, warm and wetter climates (e.g. tropical rain forest). Pyroclimate had no significant effect on the distribution of seed dormancy. The environmental drivers considered in this study had a comparatively low predictive power, suggesting that macroclimate is just one of several global drivers of seed dormancy.

Unexpected consequences of afforestation in degraded drylands: Divergent impacts on soil and vegetation.

Forestry has long been considered an effective means of restoring degraded drylands worldwide. Often, afforestation in such lands relies on the establishment of runoff harvesting systems that are formed as contour bench terraces on hillslopes, increasing water availability for the planted trees and shrubs. The construction of terraces requires intensive earthworks by heavy machinery. This study assessed the long-term (>10 yrs) effects of forestry-related land-use change on soil properties and herbaceous vegetation in 16-year-old and 12-year-old afforestation sites (established in 2005 and 2009), and in nearby control ("natural") areas in the semi-arid northern Negev, Israel. Mean herbaceous vegetation height in the 2005 afforestation sites (12.1 cm) was significantly (P = 0.0009) and 23% greater than in the control areas (9.8 cm), whereas in the 2009 afforestation sites (6.2 cm) it was 37% lesser than in the control areas. Mean herbaceous vegetation aboveground biomass was similar in the 2005 afforestation (0.39 Mg ha-1) and control areas (0.38 Mg ha-1), and almost significantly (P = 0.0510) and twofold greater than in the 2009 afforestation sites (0.19 Mg ha-1). The effect of hillslope aspect on these variables was substantial; their mean values were higher in the northern (mesic) hillslopes than in the southern (xeric) hillslopes. Soil samples were obtained from depths of 0-5 and 5-10 cm and physio-chemo-biological properties were assessed in the laboratory. The overall soil quality - as calculated by two soil quality indices (SQIs), including the generalized SQI (SQIgen) and the minimum dataset SQI (SQIMDS) - was significantly (P < 0.0001 for both indices) and 13-22% greater in the control areas (0.52 and 0.61, respectively) than that in the afforestation treatments (0.44-0.46 and 0.50-0.51, respectively). These results are generally attributed to the removal of soil's A-horizon during earthworks, and the exposure of the underlying B-horizon. The similar SQI values of both hillslope aspects, as well as of both soil depths, indicate the generally degraded state of the entire region. In conclusion, while contour bench terracing may facilitate the recovery of herbacaeous vegetation to some extent, the effectiveness of this practice for soil restoration is questionable. Overall, insights of this study demonstrate a caveat that converting natural drylands to forestry systems may not yield sufficient ecological benefits, and therefore should be implemented with caution.