Algal supplements can improve crop productivity and afford protection against abiotic stress by virtue of their rich content of plant nutrients and bioactive compounds. The present work investigates the relative efficiency of the biomass and extract of the brown alga Dictyota dichotoma in protection of rice against salinity and water stress. Rice (Oryza sativa L.) cv. Sakha 101 was grown on a silty clay soil amended with the aqueous extract and powder of D. dichotoma under NaCl and PEG 6000 stress at water potential of − 0.492 MPa. Abiotic stress, particularly water stress, reduced rice growth and concentrations of K⁺ and protein but increased soluble sugars, starch, proline and Na⁺ concentrations of plant tissues, with counterbalancing effect of algal amendment. The benefit of algal amendment was greater for algal extract than algal powder and under water stress than salt stress. Algal amendment and abiotic stress promoted catalase and peroxidase activities in rice leaves with variable effect on polyphenol oxidase. The benefit of D. dichotoma to rice can be related to macro- and micro-nutrients, growth hormones, phenolics, flavonoids, sterols, vitamins and fucoidan. The production of toxic intermediates as a result of fermentation of the algal biomass in the paddy soil might reduce the benefit of algal amendment. Although rice is salt-sensitive, it is more resistant to salt stress than to drought stress. The ability of rice to retain Na⁺ in the root is pivotal for stress resistance, but the role of K⁺ partitioning is less evident.

中文翻译：

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褐藻 Dictyota dichotoma (Hudson) 的水提取物和粉末可以不同程度地减轻非生物胁迫对水稻 (Oryza sativa L.) 的影响。


藻类补充剂富含植物营养素和生物活性化合物，可以提高作物生产力并抵御非生物胁迫。目前的工作研究了褐藻Dictyota dichotoma的生物量和提取物在保护水稻免受盐分和水分胁迫方面的相对效率。水稻 ( Oryza sativa L.) cv. Sakha 101 生长在用芒萁水提取物和粉末改良的粉质粘土上，在 NaCl 和 PEG 6000 胁迫下，水势为 − 0.492 MPa。非生物胁迫，特别是水分胁迫，降低了水稻生长以及 K ⁺和蛋白质的浓度，但增加了植物组织的可溶性糖、淀粉、脯氨酸和 Na ⁺浓度，并具有藻类改良剂的平衡作用。藻类改良剂的益处对于藻类提取物比藻粉更大，并且在水胁迫下比盐胁迫下的益处更大。藻类改良和非生物胁迫促进了水稻叶片中过氧化氢酶和过氧化物酶的活性，对多酚氧化酶具有不同的影响。芒萁对水稻的益处可能与大量和微量营养素、生长激素、酚类、类黄酮、甾醇、维生素和岩藻依聚糖有关。稻田土壤中藻类生物质发酵产生的有毒中间体可能会降低藻类改良剂的效益。尽管水稻对盐敏感，但它对盐胁迫的抵抗力比对干旱胁迫的抵抗力更强。水稻根部保留Na ⁺的能力对于抗逆性至关重要，但K ⁺分配的作用不太明显。