干旱胁迫下不同圆齿野鸦椿家系苗木生理生化指标的变化

Physiological and biochemical indexes changes of the seedlings in different families of Euscaphis konishii under drought stress

【目的】比较干旱胁迫下不同圆齿野鸦椿家系苗木生理生化指标的变化情况,为苗期抗旱性强的家系筛选及推广应用提供理论依据。【方法】以7个生长速度较快的圆齿野鸦椿家系二年生苗为材料进行盆栽试验,分析对照、轻度干旱、中度干旱和重度干旱4种处理下各家系苗木叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性、可溶性糖(SP)、可溶性蛋白(Pro)和丙二醛(MDA)6个生理生化指标的变化情况;并以相关分析结果为基础,结合隶属函数法对7个圆齿野鸦椿家系叶片的6个生理生化指标进行综合分析及抗旱性综合评价。【结果】随着干旱胁迫程度的加强,7个圆齿野鸦椿家系二年生苗6个生理生化指标的变化基本趋于一致,叶片SOD、POD和CAT活性增强,SP、Pro和MDA含量增加,但各指标的变化程度因家系不同而存在一定差异。FJ-JO-032家系叶片SOD活性在各处理中均处于较高水平;JX-QN-002家系叶片POD、CAT活性在各处理中也均处于较高水平;FJ-JO-008家系叶片SP含量在各处理中的含量较高,且其叶片Pro和MDA含量在不同干旱胁迫处理下的变化幅度最大。不同圆齿野鸦椿家系叶片CAT活性、POD活性、Pro含量和MDA含量与基质水含量(WC)呈极显著负相关(P<0.01);叶片SOD活性与基质WC呈显著负相关(P<0.05);叶片SP与基质WC无显著相关性(P>0.05)。7个圆齿野鸦椿家系的平均隶属函数值即抗旱性排序为FJ-JO-008<JX-DY-003<FJ-JO-032<GD-SX-005<JX-QN-002<FJ-JO-014<JX-XF-015。【结论】叶片CAT活性、POD活性、Pro含量、MDA含量和SOD活性可作为判断圆齿野鸦椿苗木抗旱能力的关键性指标。在7个圆齿野鸦椿家系中,JX-XF-015家系抗旱性最强,FJ-JO-014家系次之,FJ-JO-008家系最弱,故JX-XF-015和FJ-JO-014家系更适宜在生产上推广应用。

【Objective】Comparing the changes of physiological and biochemical indexes of seven Euscaphis konishii families under drought stress,which provided a theoretical reference for the selection and popularization of families with strong drought resistance at seedling stage.【Method】Seven families of E.konishii with fast growth at seedling stage were selected and their two-year seedlings were used for pot experiments.The changes of six physiological and biochemical indexes including superoxide dismutase(SOD)activity,peroxidase(POD)activity,catalase(CAT)activity,soluble sugar(SP)content,soluble protein(Pro)content and malondialdehyde(MDA)content of the sample in leaves under four treatments including control,mild drought,moderate drought and severe drought were studied.Based on the results of correlation analysis,combined with the membership function method,six physiological and biochemical indexes of leaves of seven families were analyzed and drought resistance was evaluated.【Result】With the increase of drought stress in the twoyear seedlings of seven families,the changes of six physiological and biochemical indicators were basically the same.The activities of SOD,POD and CAT in leaves increased,and the contents of SP,Pro and MDA increased,but the change degree of each index varied according to different families.The SOD activity of FJ-JO-032 leaves was at a high level among all treatments;the POD and CAT activities of JX-QN-002 leaves were also at a high level among all treatments.The SP content of FJ-JO-008 leaves was high among all treatments,and the contents of Pro and MDA in leaves changed the most under different drought stress treatments.The CAT activity,POD activity,Pro content and MDA content of E.konishii leaves of different families were extremely negatively correlated with substrate water content(WC)(P<0.01);SOD activity of leaves was significantly negatively correlated with substrate water content(P<0.05);SP had no significant correlation with substrate water content(P>0.05).According to the average membership function value(drought resistance),the order of their seedlings resistance from weak to strong was as follows:FJ-JO-008<JX-DY-003<FJ-JO-032<GD-SX-005<JX-QN-002<FJ-JO-014<JX-XF-015.【Conclusion】Leaf CAT activity,POD activity,Pro content,MDA content and SOD activity can be key indicators for judging the drought resistance of E.konishii seedlings.Among the seven families of the E.konishii,JX-XF-015 is the strongest on drought resistance,followed by FJ-JO-014,and FJ-JO-008 is the weakest.Families JX-XF-015 and FJ-JO-014 are more suitable for promotion and application in production.