Department of Agricultural, Forest and Food Sciences, University of Torino, Largo P. Braccini 2, 10095, Grugliasco, Italy.
Department of Life Sciences and Systems Biology, University of Torino, Via Quarello 15/A, 10135, Torino, Italy.
Plant Physiol Biochem. 2021 Sep;166:1076-1086. doi: 10.1016/j.plaphy.2021.07.015. Epub 2021 Jul 13.
Recently, biostimulants have been used in sustainable agriculture as priming agents able to increase crop tolerance to abiotic stressors. Here, a soil application of GHI_16_VHL, a plant protein hydrolysate-based biostimulant, was tested for its capability to mitigate severe water stress effects on Capsicum annuum at flowering time. The biostimulant influence on plant physiological status was monitored upon stress and its relief, by measuring chlorophyll levels, stomatal density, stem water potential, leaf gas exchanges and plant growth. Moreover, leaf osmoregulation and oxidative stress levels were also evaluated by quantifying free proline, total non-structural carbohydrates (NSC), ROS-scavenging activity and HO level. Although biostimulant-primed plants showed a quicker decrease of stem water potential with respect to untreated plants upon drought imposition, they recovered faster probably due to the higher leaf osmolyte accumulation, namely NSC during drought. Moreover, leaf gas exchange recovery was prompted in biostimulant-treated plants, which showed an incremented stomatal density and the same chlorophyll level of well-watered plants at the end of the recovery phase. Hydrogen peroxide level was significantly lower during stress and early recovery in biostimulant primed plants, probably due to the higher catalase activity in treated plants before drought or to the higher level of non-enzymatic antioxidant scavengers in primed stressed plants. Finally, the biostimulant priming increased aboveground relative growth rate and final fruit yield of stressed plants. Taken together, our data suggest that the biostimulant priming treatment promotes a faster and more efficient plant recovery after drought.
最近，生物刺激素被用于可持续农业中，作为能够提高作物对非生物胁迫耐受性的引发剂。在这里，测试了一种基于植物蛋白水解物的生物刺激素 GHI_16_VHL 作为土壤应用，以观察其在开花期减轻辣椒严重水分胁迫的能力。通过测量叶绿素水平、气孔密度、茎水势、叶片气体交换和植物生长，监测生物刺激素对植物生理状态的影响，以及在缓解胁迫时的影响。此外，还通过定量测定游离脯氨酸、总非结构性碳水化合物（NSC）、ROS 清除活性和 HO 水平来评估叶片渗透调节和氧化应激水平。尽管生物刺激素处理的植物在干旱胁迫下的茎水势比未处理的植物更快下降，但它们恢复得更快，可能是由于在干旱期间积累了更高的叶片渗透调节物质，即 NSC。此外，生物刺激素处理的植物的叶片气体交换恢复更快，在恢复阶段结束时，它们的气孔密度增加，并且具有与充分供水植物相同的叶绿素水平。在生物刺激素处理的植物中，过氧化氢水平在胁迫和早期恢复期间显著降低，这可能是由于在干旱前处理植物中的过氧化氢酶活性较高，或者在胁迫的处理植物中积累了更高水平的非酶抗氧化剂清除剂。最后，生物刺激素引发处理增加了受胁迫植物的地上相对生长率和最终果实产量。总之，我们的数据表明，生物刺激素引发处理促进了植物在干旱后更快、更有效的恢复。
