Effects of drought-rewatering on root development,photosynthetic physiology and yield formation of peanut during flowering-pegging stage
Root morphology,photosynthetic characteristics,and yield formation of peanut genotypes were in-vestigated under drought-rewatering conditions during the flowering and sub needling stages to elucidate the physio-logical and ecological mechanisms by which drought stress affects high-yield peanut production. Drought-tolerant varieties NH9 and HY22,as well as drought-sensitive varieties NH16 and NH21,were used as test materials in pot-ting experiments with controlled water supply. The results demonstrated that drought stress during the flowering-needling stage significantly impeded root dry matter accumulation in all four peanut varieties. The degree of inhibi-tion increased with prolonged stress duration,resulting in decreases ranging from 11.22％ to 21.01％,11.83％ to 14.68％,38.78％ to 44.40％,and 31.94％ to 40.16％ for NH9,HY22,NH16,and NH21 respectively. Under drought stress,the photosynthetic gas exchange parameters and chlorophyll fluorescence parameters of the four peanut vari-eties were significantly reduced. However,there was an increase in chlorophyll content,and NH9 and HY22 exhibit-ed relatively higher values of Gs and Ci compared to NH16 and NH21. The impact on chlorophyll fluorescence pa-rameter values (Fv/Fm,ΦPSII,Rfd,qP) was less pronounced,while the increase in NPQ and chlorophyll content did not reach a significant level. Drought stress during flowering and needle-down stages had a substantial effect on peanut yield. The yield per plant decreased by 3.67％-13.04％,4.32％-13.04％,18.19％-36.61％,and 14.53％-39.25％ for NH9,HY22,NH16,and NH21,respectively. The reduction in yield for drought-tolerant varieties was primarily attributed to a decrease in the number of full fruits per plant;whereas for drought-sensitive varieties it was also due to a decrease in the number of full fruits per plant with additional influence from other factors such as pod formation. After re-watering,the root growth,dry matter accumulation,and photosynthetic characteristics of NH9 and HY22 were rapidly restored to normal levels,even exhibiting super-compensatory effects. Meanwhile,the inhibitory effect on NH16 and NH21 was alleviated but still differed from the control group,particularly in terms of indicators such as root dry weight,root surface area,Pn (photosynthetic rate),and Rfd (quantum yield of PSII). Over-all,variations in peanut genotype yield reduction primarily resulted from differences in the number of full fruits per plant. In conclusion,the distinct response patterns to drought stress among different peanut genotypes can be attrib-uted to the superior drought resistance of NH9 and HY22 due to their well-developed root morphology and adapted photosynthetic capacity.
peanutsdrought stressflowering and sub needling stageroot developmentphotosynthetic characteristicsyield
万方数据
维普
