核桃苗木对模拟降雨变化的生理响应

Physiological Response of Walnut Seedlings to Simulated Rainfall Changes

为选育适宜的核桃树种,做到适地适树,探究核桃树响应水分变化的生理机制,通过人工控制降雨量(-50%、-25%、CK、+25%、+50%),采用盆栽苗木法测定3个核桃品种苗木的叶片相对含水量(RWC)、水分饱和亏缺(WSD)以及可溶性糖(SS)、可溶性蛋白(SP)、脯氨酸(Pro)、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性、叶绿素a、叶绿素b、总叶绿素和丙二醛(MDA)含量,并通过灰色关联度法分析各指标与核桃苗木水分适应性的关系。结果表明,模拟降雨导致核桃苗木的RWC、叶绿素a、叶绿素b和总叶绿素含量随着降雨量的增加逐步递增;WSD、SS、SP、Pro、MDA含量以及SOD、POD、CAT活性随着降雨量的增加逐步递减,且不同品种反应变化程度不同;灰色关联度分析结果显示,各项生理指标与核桃苗木水分适应性的关联顺序为SOD>MDA>叶绿素b>SP>叶绿素a>POD>RWC>WSD>Pro>SS>CAT。SOD的关联度大于0.70;MDA和叶绿素b的关联度在0.65以上;与降雨量+25%相比,降雨量+50%时香玲RWC及WSD并未发生变化,叶绿素a、叶绿素b和总叶绿素则递减,MDA含量有所上升;降雨-50%时,香玲中SOD和POD活性比降雨量-25%时有所降低。因此,核桃栽植时应注意,香玲不适于较干旱及较湿润地区,辽核1号对水分适应性较强,清香次之。本研究为核桃生产中合理栽植及水分管理提供了理论参考。

In order to select suitable walnut species, we should make appropriate trees and explore the physiological mechanism of response to moisture changes.Through the artificial precipitation environment(-50%,-25%, CK, +25%, +50%), this study used the potted seedlings method were adopted to study leaf relative water content(RWC), water saturation deficit(WSD), soluble sugar(SS),soluble protein(SP), proline(Pro), superoxide dismutase(SOD), peroxidase(POD), catalase(CAT), chlorophyll a and chlorophyll b, total chlorophyll, malondialdehyde(MDA) content, and the relationship between each index and the ability of walnut seedlings to adapt to water changes by grey correlation analysis. The results showed that the simulated rainfall caused the RWC, chlorophyll a, chlorophyll b and total chlorophyll content to gradually increase with the increase of precipitation amount;the contents of WSD, SS, SP, Pro, MDA, SOD, POD and CAT gradually decreased with the increase of precipitation amount,and the degree of change in the response of different varieties was different;the results of grey correlation analysis showed that correlation between physiological indexes and water fitness of walnut seedlings followed the order of SOD > MDA > chlorophyll b > SP > chlorophyll a >POD > RWC > WSD > Pro > SS > CAT. The correlation degree of SOD was greater than 0.70;the correlation degree between MDA and chlorophyll b were above 0.65. When the precipitation amount was +50%, compared with the precipitation amount of +25%, the RWC and WSD of Xiangling did not change that much, the chlorophyll a, chlorophyll b and total chlorophyll decreased, and the MDA content increased. When the precipitation amount was-50%,the activity of SOD and POD in Xiangling were lower than the precipitation amount was-25%. Combined with the results of this study, it is suggested that in the future planting of walnuts, Xiangling is not suitable for growing in relatively arid and humid regions,Liaohe1 has strong adaptability in different rainfall conditions, followed by Qingxiang. The research provided a theretical relerence for rational planting and water management in walnut production.