An investigation was undertaken during rabi-summer season of 2016-17 in the Department of Seed Science and Technology, OUAT, Bhubaneswar to study the efficiency of some osmoprotectants in mitigating high temperature stress by improving growth, seed yield and quality of rice cv. Naveen. The field experiment was conducted in Split Plot Design, with three replications. The main plot factor was three dates of sowing (D₁ – 30^th November, D₂ – 15^th December and D₃ – 30^th December). The sub-plot factor was foliar spray of chemicals at vegetative and seed filling stages: Control (T₀), 600 ppm Glycine betaine (T₁), 400 ppm Salicylic acid (T₂), 800 ppm Salicylic acid (T₃), 10 ppm Ascorbic acid + 1.3% Citric acid (T₄), 150 ppm α-Tocopherol (T₅), 1.0% Potassium chloride (T₆), 5 ppm Brassinolides (T₇) and 10 ppm Brassinolides (T₈). Observations on various phenological, seed yield and quality parameters were recorded. With advancement in sowing time, there was significant decrease in the chlorophyll content of leaves. The chlorophyll content of leaves after two days of spraying as slightly higher than that prior to spraying in all the treatments. Maximum chlorophyll content was recorded with spray treatment of 0 ppm salicylic acid at both the stages of observation. Significantly higher pollen viability and seed set were recorded with first date of sowing (D₁), compared to second and third dates of sowing (D₂ and D₃, respectively). Among the treatments, pollen viability was highest with 10 ppm brassinolides and 400 ppm salicylic acid. Seed set was highest with 10 ppm brassinolides and 800 ppm salicylic acid. With advancement in sowing time, there was decrease in membrane stability index of leaves. The MSI of leaves after two days of spraying was slightly higher than that prior to spraying in all treatments. Maximum MSI was recorded with spray treatment of 400 ppm salicylic acid (T₂) during vegetative and seed filling stages. The treatments T₂, T₄ and T₈ produced highest increase in MSI compared to that before spraying during both stages. Higher seed yield was obtained from D₁, compared to delayed sowing. Mean seed yield from D₁ was 53.76 q/ha, as against 48.99 q/ha and 44.51 q/ha from D₂ and D₃, respectively. Spraying of 800 ppm salicylic acid and 10 ppm brassinolides gave highest seed yields from each date of sowing. Seed yields from D₃T₀ and D₂T₀ (35.33 q/ha and 39.72 q/ha, respectively) were significantly lower than all treatment combinations, including D₁T₀ (51.83 q/ha). Increase in seed yields due to various treatments as against the control was more pronounced in D₂ and D₃. The first date of sowing (D₁) produced seeds with higher 1000-seed weight (22.62 g), compared to D₂ and D₃ (20.27 g and 19.36 g, respectively). Among the treatments, higher 1000-seed weights were recorded with the treatments T₃ and T₈ (21.51 g and 21.43 g, respectively), while lowest 1000-seed weight (18.76 g) was recorded with the Control. Seeds produced from D₁ recorded higher germination and seed vigour. All the treatments recorded improvement in germination and vigour of seeds with three dates of sowing. Treatments T₃, T₇ and T₈ gave highest improvement in seed germination over control. Under accelerated ageing treatment, T₃ recorded highest germination followed by T₈. Dates of sowing and treatment sprays had no influence on electrical conductivity of seed leachate. Hence, the present study demonstrated that foliar sprays at vegetative and seed filling stages with 800 ppm salicylic acid or 10 ppm ascorbic acid + 1.3% citric acid or 10 ppm brassinolides were quite effective in alleviating adverse effects of high temperature during flowering and seed set, through increased chlorophyll content of leaves, improved membrane stability, higher pollen viability and seed set, thus improving seed yield and quality of rice.

中文翻译：

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通过在高温胁迫下叶面喷洒渗透保护剂提高水稻（Oryza sativa L.）的生长和种子产量

在布巴内斯瓦尔OUAT种子科学与技术系2016-17夏季狂犬病季节进行了一项调查，以研究某些渗透保护剂通过改善水稻简历的生长，种子产量和质量来缓解高温胁迫的效率。纳文 现场实验是在Split Plot Design中进行的，一式三份。主要地积因子是三个播种日期（11月_1日至30^日，12月_2日至15^日和12月_3日至30^日）。次图因素是在营养和种子填充阶段进行的叶面化学喷雾：对照（T ₀），600 ppm甘氨酸甜菜碱（T ₁），400 ppm水杨酸（T₂），800 ppm水杨酸（T ₃），10 ppm抗坏血酸+ 1.3％柠檬酸（T ₄），150 ppmα-生育酚（T ₅），1.0％氯化钾（T ₆），5 ppm油菜素内酯（T ₇）和10 ppm的油菜素内酯（T ₈）。记录了各种物候，种子产量和质量参数的观察结果。随着播种时间的增加，叶片的叶绿素含量显着下降。在所有处理中，喷洒两天后叶片的叶绿素含量略高于喷洒前。在两个观察阶段，通过喷雾处理0 ppm水杨酸记录了最大叶绿素含量。与第二和第三次播种（D ₂和D ₃）相比，第一次播种（D ₁）记录的花粉活力和种子结实显着更高。， 分别）。在这些处理中，花粉生存力最高的是10 ppm的油菜素内酯和400 ppm的水杨酸。10 ppm的油菜素内酯和800 ppm的水杨酸使结实率最高。随着播种时间的增加，叶片的膜稳定性指数降低。在所有处理中，喷洒两天后叶片的MSI略高于喷洒前。在营养和种子填充阶段，以400 ppm水杨酸（T ₂）进行喷雾处理，记录到最大MSI 。在两个阶段中，与喷雾之前相比，处理T ₂，T ₄和T ₈产生的MSI最高。从D ₁获得更高的种子产量，相比延迟播种。D _1的平均种子产量为53.76 q / ha，而D ₂和D _3的平均种子产量分别为48.99 q / ha和44.51 q / ha 。从每次播种开始，喷800 ppm水杨酸和10 ppm油菜素内酯可获得最高的种子产量。D ₃ T ₀和D ₂ T _0的种子产量（分别为35.33 q / ha和39.72 q / ha）显着低于所有处理组合，包括D ₁ T ₀（51.83 q / ha）。在D ₂和D ₃中，与对照相比，由于各种处理，种子产量的增加更为明显。播种的第一天（D ₁）生产的种子比D ₂和D ₃（分别为20.27 g和19.36 g）具有更高的1000种子重量（22.62 g ）。在这些处理中，用处理T ₃和T ₈记录的较高的1000粒重（分别为21.51 g和21.43 g），而使用对照记录的最低1000种子的重量（18.76 g）。由D ₁产生的种子具有更高的发芽和种子活力。所有处理均记录了三个播种期种子发芽和活力的提高。处理T ₃，T ₇和T ₈与对照相比，种子发芽得到最大改善。在加速老化处理下，T ₃记录到最高发芽率，其次是T ₈。播种和处理喷雾的日期对种子浸出液的电导率没有影响。因此，本研究表明，在营养和种子充实阶段，用800 ppm水杨酸或10 ppm抗坏血酸+ 1.3％柠檬酸或10 ppm油菜素内酯的叶面喷洒在缓解开花和结实期间高温的不利影响方面非常有效，通过增加叶片的叶绿素含量，改善膜的稳定性，提高花粉的活力和结实，从而提高水稻的种子产量和品质。