Mid-season nitrogen application strategies for rice varieties differing in panicle size

-The application of herbicides, even if selective, can cause biochemical and physiological changes, resulting in oxidative stress. This stress comes from the accumulation of reactive oxygen species produced due to exposure to the herbicide. However, plants have developed defense strategies, which can be enzymatic or non-enzymatic. The objective of this study was to evaluate the morphological and metabolic changes such as photosynthetic parameters, oxidative damage and antioxidant enzyme activity of rice plants after applying herbicides. For this, a study was conducted in a greenhouse and laboratory and the treatments consisted of application of imazapic + imazapyr, quinclorac, bentazon, cyhalofop-butyl, penoxsulan, bispyribac-sodium and carfentrazone-ethyl, in addition to control without herbicide. The phytotoxicity in plants was strong and there was a reduction in photosynthesis, stomatal conductance and efficiency of water use in plants treated with carfentrazone-ethyl. Furthermore, the application of carfentrazone-ethyl resulted in lower chlorophylls and carotenoids and increased lipid peroxidation and proline accumulation. Changes in the activity of enzymes belonging to the antioxidant system were inspected by applying herbicides. The application of herbicide alters the physiology of rice plants, triggering responses to oxidative stress, which are more pronounced when used carfentrazone-ethyl. Keywords:Oryza sativa, oxidative stress, lipid peroxidation, selectivity. RESUMO -

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“…Biochemical and physiological changes in rice plants due to ... of memory for the next generation (Zhang et al, 2013).…”

Section: Resultsmentioning

confidence: 99%

Biochemical and Physiological Changes in Rice Plants Due to the Application of Herbicides1

et al. 2016

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“…Further studies showed that super rice has a lower NSC (sugar) to spikelet ratio at heading time, and this ratio was positively and significantly correlated with sink activity at the initial grain filling stage [36,38] . Application of potassium at the panicle initiation stage and/or N fertilizer at the spikelet differentiation stage can significantly increase the sugarspikelet ratio at the heading time through increasing NSC accumulation in stems 0-15 days before heading, and consequently, increase sink activity at the initial grain filling stage, leading to an improvement in grain fill in inferior spikelets [38,43] . Therefore, increasing sugar-spikelet ratio at heading can be considered as an important approach to improving grain fill in inferior spikelets.…”

Section: Improving Grain Fill In Later-flowering Inferior Spikeletsmentioning

confidence: 99%

Approaches to achieve high grain yield and high resource use efficiency in rice

Yang¹

2015

Front. Agr. Sci. Eng.

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This article discusses approaches to simultaneously increase grain yield and resource use efficiency in rice. Breeding nitrogen efficient cultivars without sacrificing rice yield potential, improving grain fill in laterflowering inferior spikelets and enhancing harvest index are three important approaches to achieving the dual goal of high grain yield and high resource use efficiency. Deeper root distribution and higher leaf photosynthetic N use efficiency at lower N rates could be used as selection criteria to develop N-efficient cultivars. Enhancing sink activity through increasing sugar-spikelet ratio at the heading time and enhancing the conversion efficiency from sucrose to starch though increasing the ratio of abscisic acid to ethylene in grains during grain fill could effectively improve grain fill in inferior spikelets. Several practices, such as post-anthesis controlled soil drying, an alternate wetting and moderate soil drying regime during the whole growing season, and non-flooded straw mulching cultivation, could substantially increase grain yield and water use efficiency, mainly via enhanced remobilization of stored carbon from vegetative tissues to grains and improved harvest index. Further research is needed to understand synergistic interaction between water and N on crop and soil and the mechanism underlying high resource use efficiency in high-yielding rice.

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“…Consequently, research results often vary according to these different indexes. REN is commonly used to evaluate the actual use efficiency and loss rate of N [26]. In a previous study, REN was found to range between 30% and 40% under CF in China [18], which is lower than in other developed countries, such as USA, Canada and so on.…”

Section: Nue Consistency and Conversion Under Cf And Ofmentioning

confidence: 99%

“…The literature on NUE tends to focus on CF or inorganic/organic fertilization, rather than OF [26,31,32]. Application of organic-inorganic compound fertilizer was previously found to have a positive effect on soil organic carbon accumulation and crop productivity in rice fields, reducing chemical fertilizer use, optimizing the physical qualities of paddy soil, and improving long-term sustainability through increased N efficiency, possibly as a result of enhanced microbial activity [31][32][33].…”

Section: Nue Consistency and Conversion Under Cf And Ofmentioning

confidence: 99%

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Synergy and Transition of Recovery Efficiency of Nitrogen Fertilizer in Various Rice Genotypes under Organic Farming

et al. 2016

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Despite the growing demand for organic products, research on organic farming (OF) such as genotype screening, fertilizer application and nutrition uptake remains limited. This study focused on comparisons of the apparent recovery efficiency of nitrogen fertilizer (REN) in rice grown under OF and conventional farming (CF). Thirty-two representative conventional Japonica rice varieties were field grown under five different treatments: control check (CK); organic farming with low, medium and high levels of organic fertilizer (LO, MO and HO, respectively); and CF. Comparisons of REN between OF and CF classified the 32 genotypes into four types: high REN under both OF and CF (type-A); high REN under OF and low REN under CF (type-B); low REN under OF and high REN under CF (type-C); and low REN under both OF and CF (type-D). Though the yield and REN of all the rice varieties were higher with CF than with OF, organic N efficient type-A and B were able to maintain relatively high grain yield under OF. Physiological activities in flag leaves of the four types from booting to maturity were subsequently investigated under OF and CF. Under OF, high values of soil and plant analyzer development (SPAD) and N were observed in type-B varieties, while in contrast, both indexes slowly decreased in type-C varieties under CF. Moreover, the decline in N content in type-C and D varieties was greater under OF than CF. The decrease in glutamine synthetase (GS), glutamic-pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) activity in flag leaves was smaller under OF than CF in type-A and B varieties, while in contrast, type-C and D varieties showed an opposite trend. The findings suggest that OF slows the decline in key enzymes of N metabolism in organic N-efficient type rice, thus maintaining a relatively high capacity for N uptake and utilization and increasing yield during the late growth period. Accordingly, we were able to screen for varieties of rice with synergistically high REN and high grain yield under OF.

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Mid-season nitrogen application strategies for rice varieties differing in panicle size

Cited by 113 publications

References 23 publications

Biochemical and Physiological Changes in Rice Plants Due to the Application of Herbicides1

Biochemical and Physiological Changes in Rice Plants Due to the Application of Herbicides1

Approaches to achieve high grain yield and high resource use efficiency in rice

Synergy and Transition of Recovery Efficiency of Nitrogen Fertilizer in Various Rice Genotypes under Organic Farming

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