Biostimulants can be used as an alternative to fertilizers to overcome the effect of nutrient deficiency in plants. Yeast is a biostimulant, having the capacity to modify physiological processes in plants by improving germination and seedling growth under environmental stress. The effects of yeast extract, a sustainable biostimulant derived from yeast (Saccharomyces cerevisiae) containing all the nutritive values, amino acids, vitamins, and growth factors, were investigated in rice (Oryza sativa). Various growth parameters, Chlorophyll a fluorescence, PS II, metabolites accumulation, and antioxidative function of enzymatic (SOD, CAT, APX, GPOX) as well as non-enzymatic (phenol, AsA, and GSH) antioxidant were analyzed in two rice varieties (Hraswa-tolerant and Manu ratna-sensitive) in both yeast extract primed and non-primed seeds subjected to nutrient-deficient soil conditions. The application of the biostimulant (yeast extract) as a priming agent increased the biomass, photosynthetic pigment, modified chlorophyll a fluorescence-related parameters, and also enhanced the photosystem activities of seedlings, supported by decreased content of ROS and MDA in primed seeds when compared to non-primed ones. These changes were accompanied by a significant enhancement in osmolytes and non-enzymatic antioxidants (AsA, GSH, and total phenolics). In general, yeast priming under nutrient-deficient conditions appeared to stimulate the activities of SOD, CAT, and APX in var. Hraswa while GPOX was dramatically upregulated in var. Manu ratna. Thus, these results speculate that yeast priming under nutrient-deficient conditions maintained cell homeostasis and provided better adaptation to the stress conditions in both tolerant as well as sensitive varieties of rice seedlings.

生物刺激剂可以用作肥料的替代品，以克服植物营养缺乏的影响。酵母是一种生物刺激剂，具有通过改善环境胁迫下的发芽和幼苗生长来改变植物生理过程的能力。在稻米（Oryza sativa）中研究了酵母提取物的效果，酵母提取物是一种源自酵母（Saccharomyces cerevisiae）的可持续生物刺激剂，其中含有所有营养价值，氨基酸，维生素和生长因子。 ）。在两个水稻品种中分析了各种生长参数，叶绿素a荧光，PS II，代谢产物积累以及酶促（SOD，CAT，APX，GPOX）和非酶促（酚，AsA和GSH）抗氧化剂的抗氧化功能（受到营养不足的土壤条件的酵母提取物初免和初免种子中的耐Hraswa和Manu Ratna敏感性）。生物刺激剂（酵母提取物）作为引发剂的应用增加了生物量，光合色素，改性叶绿素a。与未引发的种子相比，发芽种子中的ROS和MDA含量降低，支持了与荧光有关的参数，并增强了幼苗的光系统活性。这些变化伴随着渗透压和非酶促抗氧化剂（AsA，GSH和总酚类）的显着增强。通常，在营养缺乏的条件下启动酵母似乎可以刺激var中的SOD，CAT和APX活性。Hraswa，而GPOX在var中显着上调。Manu Ratna。因此，这些结果推测，在营养缺乏条件下的酵母引发可以维持细胞稳态，并在水稻幼苗的耐性和敏感品种中都能更好地适应胁迫条件。