Improving water use efficiency and salt-drought tolerance in rice seedlings via gibberellic acid seed soaking and light supplementation
LIN Shimiao
ZHU Mei
LIU Shuoshuo
SUN Danchen
Abstract：[Objective]Rice seedlings are susceptible to salt and drought stresses.Herein,we investigate the efficacy of seed soaking with gibberellic acid combined with red-blue light supplementation on water use efficiency and stress resistance of rice seedlings under salt and drought stress.[Method]Rice variety'Jingzhan No.1'was used in the experiment.The agronomic treatments included seed soaking in distilled water without supplemental lighting(WN)and seed soaking in a solution with 150 mg/L gibberellic acid combined with nighttime far-red-blue light supplementation(GL).There were two drought treatments with PEG-6000 concentrations in the medium set at 10%(T1)and 15%(T2)respectively,two salinity treatments with NaCl concentrations of 0.075 mol/L(T3)and 0.15 mol/L(T4)respectively,and four combined salt-drought treatments formed by combining T1-T2 with T3-T4.During the experiment,we measured dry matter accumulation,root-to-shoot ratio,photosynthetic traits,water use efficiency,and antioxidant and oxidative stress indicators.[Result]The GL treatment alleviated the inhibitory effects of salt and drought,both individually and in combination,on seedling growth.When other conditions were the same,GL increased aboveground and belowground dry weights by 3.22%-12.90%and 17.19%-40.63%,respectively,and root-to-shoot ratio by 14.56%-54.08%compared with the WN treatment.GL also improved net photosynthetic rate and leaf water use efficiency by 0.81%-41.81%and 2.19%-71.47%,respectively.GL enhanced the activities of antioxidant enzymes(superoxide dismutase and peroxidase),while reducing catalase activity,malondialdehyde content,and hydrogen peroxide levels.Correlation analysis showed that water use efficiency was most strongly correlated with photosynthetic rate(R2=0.53)and least correlated with peroxidase activity(R2=0.071).The factors affecting water use efficiency were ranked as follows:photosynthetic rate＞malondialdehyde ≈ catalase＞superoxide dismutase＞hydrogen peroxide＞root-to-shoot ratio＞peroxidase.[Conclusion]Seed soaking in gibberellic acid solution combined with far-red-blue light supplementation improves water use efficiency and enhances salt-drought tolerance of rice seedlings primarily due to the improved carbon assimilation rather than solely because of the enhanced antioxidant enzyme activity.
Keywords：ricecombined salt-drought stressgibberellic acid seed soakingfar-red-blue light supplementationwater use efficiency
Publication Date：2026-06-30
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：9( 10-18 )