Kinetic parameters related to nitrogen uptake in 'Okinawa' peach rootstocks are altered by 'Chimarrita' scion Nitrogen uptake in 'Okinawa' peach rootstock.

BACKGROUND: The kinetic parameters of peach rootstock are a major factor contributing to its nitrogen (N) uptake efficiency, which directly affects the yield and quality parameters. However, the impact of grafting on N kinetic parameters is not sufficiently known as rootstocks are grafted with other scion cultivars before being transplanted to the field. The objective of this study was therefore to evaluate whether the grafting of 'Okinawa' rootstock with the scion cultivar 'Chimarrita' can alter the kinetic parameters related to N uptake. RESULTS: The plants were acclimatized in Hoagland solution for 21 days and, sequentially, were tested to assess the depletion of the internal reserves at 15 and 30 days in CaSO4 solution. Morphological and physiological parameters were evaluated, and kinetic parameters were calculated. The depletion period for to reach the minimum concentration (Cmin ) of NO3 - and NH4 + in the plant was 62 h and 56 h, respectively. The optimal time for internal reserve depletion for 'Okinawa' rootstock with and without the 'Chimarrita' scion was 30 days. CONCLUSION: 'Okinawa' rootstock grafted with 'Chimarrita' scion cultivar was more efficient in NO3 - and NH4 + uptake. © 2022 Society of Chemical Industry.

Physiological responses of rice (Oryza sativa L.) oszip7 loss-of-function plants exposed to varying Zn concentrations.

Rice is a daily staple for half of the world's population. However, rice grains are poor in micronutrients such as Fe and Zn, the two most commonly deficient minerals in the human diet. In plants, Fe and Zn must be absorbed from the soil, distributed and stored, so that their concentrations are maintained at sufficient but non-toxic levels. The understanding of mechanisms of Fe and Zn homeostasis in plants has the potential to benefit agriculture, improving the use of micronutrients by plants, as well as to indicate approaches that aim at biofortification of the grains. ZIP transporters are commonly associated with Zn uptake, but there are few reports about their physiological relevance in planta. Here we describe a Tos17 loss-of-function line for the Zn plasma membrane transporter OsZIP7 (oszip7). We showed that the absence of functional OsZIP7 leads to deregulated Zn partitioning, increasing Zn accumulation in roots but decreasing in shoots and seeds. We also demonstrated that, upon Zn deficiency, oszip7 plants slightly increase their photosynthetic performance, suggesting that these plants might be primed for Zn deficiency which makes them more tolerant. On the other hand, we found that Zn excess is more deleterious to oszip7 plants compared to wild type, which may be linked to secondary effects in concentrations of other elements such as Fe. Our data suggest that OsZIP7 is important for Zn homeostasis under physiological Zn concentrations, and that Fe homeostasis might be affected due to loss of function of OsZIP7.

Potential of vermicompost and limestone in reducing copper toxicity in young grapevines grown in Cu-contaminated vineyard soil.

Foliar fungicide application in grapevines increases the content of heavy metals such as copper (Cu) in vineyard soils, which may reach phytotoxic levels. The application of soil amendments such as limestone and vermicompost may reduce Cu availability and phytotoxicity. The study aimed to assess growth, physiological status and changes in root morphology in young grapevines grown for 12 months in Cu-contaminated soil with and without the application of soil amendments. Samples of a Typic Hapludalf soil were collected in a vineyard with more than 30 years of cultivation. The following treatments were used: 1) control (without amendment), 2) application of organic vermicompost (86.7 g kg-1) and 3) application of limestone (3 Mg ha-1). Grapevines (Paulsen 1103 rootstock) were transplanted and grown for 12 months in PVC soil columns. We assessed parameters of growth, photosynthesis and root morphology. Grapevines grown in soil treated with limestone showed increased growth, dry matter yield and photosynthetic efficiency. The highest Cu concentrations in root tissue were found in grapevines grown in control soil. The application of vermicompost in this study did not alleviate Cu toxicity. Grapevines grown in soil treated with vermicompost showed high manganese (Mn) concentration in shoots before the winter pruning, reflecting the high Mn concentrations in soil solution that caused Mn phytotoxicity, resulting in plant death after the winter pruning. The vermicompost used in this study is not suitable for agronomic use. The use of limestone was an effective strategy to reduce Cu availability and phytotoxicity.

Barnyardgrass control using tank-mixed herbicides with saflufenacil and its influence in photosynthesis and chlorophyll fluorescence / Controle de capim-arroz mediante associações de herbicidas com saflufenacil e influência na fotossíntese e fluorescência de clorofila

ABSTRACT: The objectives of this research were to evaluate the interaction between herbicides mixed with saflufenacil for the control of barnyardgrass and to determine the effect on photosynthetic and chlorophyll fluorescence parameters. The experiment was conducted in a greenhouse in a 2x8 factorial scheme, whose factor A tested resistant and susceptible biotypes; and factor B the herbicides: saflufenacil (70 g a.i. ha-1), clomazone (180 g a.i. ha-1), imazapyr + imazapic (73.5 + 24.5 g a.i. ha-1), and cyhalofop (360 g a.i. ha-1), the mixtures of these herbicides with saflufenacil, and control without treatment. Weed control was assessed 7, 14, 21 and 28 days after herbicide application (DAA), as well as shoot dry matter at 28 DAA, photosynthetic parameters using infrared gas analyzer (IRGA), and emission of chlorophyll a fluorescence after 24 and 28 hours of application of treatments, respectively, and interaction of herbicides. Combination of saflufenacil with the herbicides tested in general did not change the response of both barnyardgrass biotypes to the herbicides used. The resistant biotype showed a lower negative effect on chlorophyll fluorescence and photosynthesis parameters in the combination of herbicides with saflufenacil. The herbicide cyhalofop was effective for the control of ALS-susceptible and resistant barnyardgrass.

RESUMO: O objetivo deste trabalho foi avaliar a interação entre herbicidas associados ao saflufenacil para o controle de capim-arroz e a determinação do efeito dos herbicidas sobre os parâmetros fotossintéticos e de fluorescência de clorofila. O experimento foi conduzido em casa de vegetação em esquema fatorial 2x8, cujo fator A testou os biótipos resistente e suscetível; e o fator B os herbicidas: saflufenacil (70 g i.a. ha-1), clomazone (180 g i.a. ha-1), imazapyr+imazapic (73,5+24,5 g i.a. ha-1), cyhalofop (360 g i.a. ha-1), as associações desses com saflufenacil, e testemunha sem tratamento. Foi avaliado o controle aos 7, 14, 21 e 28 dias após a aplicação dos herbicidas (DAA), massa seca da parte aérea aos 28 DAA, avaliação de parâmetros fotossintéticos com analisador de gás infravermelho (IRGA) e emissão de fluorescência da clorofila a 24 e 48 horas após aplicação dos tratamentos, respectivamente, e interação dos herbicidas. A associação de saflufenacil com herbicidas testados na maior parte não modificou a resposta dos herbicidas para o controle de capim-arroz em ambos os biótipos. O biótipo resistente apresentou menor efeito negativo nos processos de fluorescência de clorofila e parâmetros de fotossíntese na associação de herbicidas com saflufenacil. O herbicida cyhalofop associado ao saflufenacil demonstra ser eficiente para o controle de capim-arroz suscetível e resistente a ALS.