| Peanut is an important oil crop and an important source of edible vegetable oil and protein in our country.Peanut seed germination process often encounters drought,low temperature and other adversities,affecting peanut seedling establishment and thus affect the later yield.This study was conducted to identify and evaluate seed vigor of peanut cultivars commonly used in production.Typical peanut cultivars with different vigor were used as materials to study the characteristics of peanut seed germination into seedlings,and decomposition and transformation of storage substances under different levels of drought and low temperature stresses.The regulation effect of seed dressing with GABA treatment on germination of peanut seeds under drought and low temperature stress was further studied to provide technical guidance for germination of peanut seeds under adverse conditions.The results are as follows:1.Differences in seed vigor of different peanut cultivarsThe seed germination and vigor indexes of 12 peanut cultivars under drought and lowtemperature stress were measured,and a principal component analysis was performed based on the drought tolerance coefficient and low-temperature tolerance coefficient of each index,respectively,to calculate the comprehensive evaluation D value,and cluster analysis was used to evaluate the germination characteristics under drought stress and germination characteristics under low-temperature stress of peanut cultivars.Based on the cluster analysis of the D value of drought tolerance coefficient,peanut cultivars were classified into three categories of good,moderate and poor germination characteristics under drought stress,LH8 and QCYD was the cultivars with good germination characteristics under drought stress.Based on the cluster analysis of D value of low-temperature tolerance coefficient,peanut cultivars were classified into three categories of good,moderate and poor germination characteristics under lowtemperature stress,and BS1016 and HY25 were cultivars with good germination characteristics under low-temperature stress.2.Effect of drought stress on seed germination and seedling establishment of peanutTo study the effects of different levels of drought stress on seed germination and seedling establishment,decomposition and transformation of storage substances in four peanut cultivars(LH8,BS1016,SH7 and HY25).The results showed that GI of the four peanut cultivars decreased significantly under mild and moderate drought stress,and VI and SL of SH7 also decreased significantly under severe drought stress.Drought stress had a great effect on the material efficiency of HY25,and the material efficiency decreased significantly and extremely significantly under moderate and severe drought.The material efficiency of other cultivars decreased significantly only under severe drought stress.Drought stress significantly decreased the soluble protein content of LH8 and HY25 at different germination times,but had no significant effect on the other two cultivars.The effects of drought stress on cysteine protease activity of different peanut cultivars were different.The cysteine protease activity of LH8 and BS1016 was significantly higher than that of the control under moderate and severe drought stress.The cysteine protease activity of HY25 and SH7 was significantly lower than that of the control at each germination time point under mild drought stress.The results indicate the cysteine protease activity under drought stress was closely related to the germination characteristics of cultivars under drought stress.3.Effect of low temperature stress on seed germination and seedling establishment of peanutTo study the effects of different levels of low temperature stress on seed germination and seedling establishment,decomposition and transformation of storage substances in four peanut cultivars(BS1016,HY25,LH8 and SH7).The results showed that GI,SL and R/S of four peanut cultivars were significantly reduced under different levels of low temperature stress.VI of HY25 decreased significantly under 19℃ and 16℃,while VI of the other three cultivars decreased significantly under the three low temperature stresses.Low temperature stress had no effect on the material efficiency of LH8 and SH7.The material efficiency of BS1016 decreased significantly at 16℃,while that of HY25 decreased significantly at 19℃ and 16℃.The soluble protein content of HY25 was significantly higher than that of the control for 24 h to 48 h of germination at 19℃ and 16℃.The soluble protein content of the other three cultivars had no significant change under different levels of low temperature stress.Low temperature stress had significant effects on cysteine protease activity during seed germination of 4 cultivars,and significantly decreased the cysteine protease activity of HY25,SH7 and LH8 at 48 h,72 h and BS1016 at different germination time points.4.Regulation of seed germination and seedling establishment of peanut seeds under drought and low temperature by seed dressing with GABALH8 and HY25 were selected to study the effects of seed dressing with GABA treatment on germination and seedling establishment under drought stress.The results showed that seed dressing with 5m M GABA treatment significantly increased VI of LH8 and HY25 under drought stress and GE,GP and GI under normal conditions.In addition,GP,GI,R/S and the soluble protein content of LH8 germinated at 24 h under drought stress also significantly increased compared with the seed dressing with water.Seed dressing with GABA treatment significantly increased the soluble protein content of HY25 germinated at 48 h and LH8 germinated at 24 h and 48 h under normal conditions.But had no significant effect on cysteine protease activity of the two cultivars under drought stress.BS1016 and LH8 were selected to study the effect of seed dressing with GABA treatment on germination and seedling establishment under low temperature stress.The results showed that seed dressing with 5m M GABA treatment significantly increased VI,SSDW,RL of BS1016 and VI of LH8 under low temperature stress.At the same time,VI and SSDW of LH8 and GE,GI and R/S of BS1016 were significantly increased under normal conditions.Seed dressing with GABA treatment had significant effects on the soluble protein content and cysteine protease activity of the two cultivars under low temperature stress.The soluble protein content of the two cultivars after 72 h of germination under low temperature was significantly increased compared with that of seed dressing with water treatment.The cysteine protease activity of BS1016 germinated at 24 h and LH8 germinated at 48 h under low temperature was significantly increased. |
PDF Full Text Request