摘要
【目的】研究酸枣Ziziphus jujuba Mill.var.spinosa对混合盐碱胁迫的生理响应机制,为今后深入探究其耐盐碱机制提供理论基础。【方法】以酸枣为试验材料,通过模拟黄河三角洲地区盐碱地土壤主要盐分组成,对酸枣幼苗实施质量分数分别为0(CK)、3‰(SA1)和6‰(SA2)的盐碱混合溶液处理,通过测定叶片和株高绝对生长量、根冠比等生长指标,叶绿素含量、PSⅡ最大光化学效率等光合生理参数,叶片和根系丙二醛(MDA)含量、根系相对电导率等膜损伤指标,以及叶片和根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性,研究不同梯度盐碱胁迫对酸枣幼苗生长及生理生化特性的影响。【结果】随着盐碱质量分数升高,较CK,SA1和SA2处理的叶片绝对生长量分别下降了51.0%、87.8%,株高绝对生长量分别下降了18.6%、58.7%,而根冠比升高了32.9%和47.9%。光合参数检测显示,较CK,SA1和SA2的叶片总叶绿素含量分别下降了20.6%,27.0%、PSⅡ最大光化学效率分别降低了8.0%、17.1%、光合性能指数分别减少了22.8%、44.5%,PSⅡ潜在光化学活性分别降低了11.5%、14.9%。盐碱胁迫显著改变了叶绿素荧光动力学特性,导致叶绿素荧光诱导动力学曲线由O—J—I—P变为O—K—J—I—P,以及ΔV_(K)、ΔV_(J)大幅增加。膜损伤指标显示,SA1和SA2处理的叶片MDA含量分别升高了91.6%、55.1%,根系MDA含量分别增加了26.4%、330.2%;根系相对电导率分别上升了43.2%、50.9%。抗氧化系统分析表明,随着盐碱胁迫程度的加剧,除叶片CAT活性外,叶片和根系的抗氧化酶系统(SOD、POD、CAT)均呈现先升后降趋势,在SA1处理下出现峰值;叶SOD和POD峰值分别为141.6、244.7 U/g,根SOD、CAT和POD峰值分别为74.6、31.2、1.5 U/g。【结论】酸枣幼苗叶片对盐碱胁迫的响应比根系更加敏感。盐碱胁迫降低了酸枣叶片的光化学效率和光合性能,且盐碱胁迫水平越高对其抑制作用越明显。3‰盐碱胁迫激活了酸枣幼苗体内的抗氧化酶系统,以保持膜系统稳定,而6‰的盐碱胁迫处理破坏了其抗氧化酶系统。
【Objective】To research the physiological response mechanism of Ziziphus jujuba Mill.var.spinosa under mixed saline-alkali stress,and provide a theoretical basis for further exploration of its saline-alkali tolerance mechanism.【Method】Using Z.jujuba Mill.var.spinosa as the experimental material,the main salt composition of saline-alkali soil in the Yellow River Delta was simulated.Seedlings were treated with saline-alkali mixed solutions at mass fractions of 0(CK),3‰(SA1),and 6‰(SA2).Growth indices(absolute growth of leaves and plant height,root-shoot ratio),photosynthetic physiological parameters(chlorophyll content,maximum photochemical efficiency of PSⅡ),membrane damage indices(MDA content in leaves and roots,relative electrical conductivity of roots),and antioxidant enzyme activities(SOD,POD,CAT in leaves and roots)were measured to investigate the effects of different gradients of saline-alkali stress on the growth and physiological-biochemical characteristics of Z.jujuba seedlings.【Result】With the increase in saline-alkali mass fraction,compared with CK,the absolute leaf growth under SA1 and SA2 decreased by 51.0%and 87.8%,respectively,and the absolute height growth decreased by 18.6%and 58.7%,while the root-shoot ratio increased by 32.9%and 47.9%.Photosynthetic parameter detection showed that compared with CK,the total chlorophyll content in leaves under SA1 and SA2 decreased by 20.6%and 27.0%,the maximum photochemical efficiency of PSⅡ(F_(v)/F_(m))decreased by 8.0%and 17.1%,the photosynthetic performance index(P_(ABS))decreased by 22.8%and 44.5%,and the potential photochemical activity of PSⅡ(F_(v)/F_(o))decreased by 11.5%and 14.9%.Saline-alkali stress significantly altered the chlorophyll fluorescence kinetic characteristics,causing the chlorophyll fluorescence induction kinetic curve to change from O-J-I-P to O-K-J-I-P,with a significant increase in ΔV_(K) and ΔV_(J).Membrane damage indices showed that the MDA content in leaves under SA1 and SA2 increased by 91.6%and 55.1%,respectively,and the MDA content in roots increased by 26.4%and 330.2%;the relative electrical conductivity of roots increased by 43.2%and 50.9%.Analysis of the antioxidant system showed that with the aggravation of saline-alkali stress,except for the CAT activity in leaves,the antioxidant enzyme systems(SOD,POD,CAT)in leaves and roots showed a trend of first increasing and then decreasing,peaking under SA1 treatment.The peak values of leaf SOD and POD were 141.6 U/g and 244.7 U/g,respectively,and the peak values of root SOD,CAT,and POD were 74.6 U/g,31.2 U/g,and 1.5 U/g,respectively.【Conclusion】The leaves of Z.jujuba seedlings are more sensitive to saline-alkali stress than the roots.Saline-alkali stress reduced the photochemical efficiency and photosynthetic performance of Z.jujuba leaves,and the inhibitory effect was more obvious with higher stress levels.3‰saline-alkali stress activated the antioxidant enzyme system in Z.jujuba seedlings to maintain membrane system stability,while 6‰saline-alkali stress damaged its antioxidant enzyme system.
作者
李新宇
由菁
董肖昌
张春梅
LI Xinyu;YOU Jing;DONG Xiaochang;ZHANG Chunmei(College of Forestry,Shandong Agricultural University,Tai’an 271018,Shandong,China;State Key Laboratory of Nutrient Use and Management,Shandong Institute of Pomology,Tai’an 271099,Shandong,China)
出处
《经济林研究》
北大核心
2025年第3期50-58,122,共10页
Non-wood Forest Research
基金
山东省重点研发计划项目(农业良种工程)(2024LZGC025)。
关键词
酸枣
盐碱胁迫
生理生化指标
叶绿素荧光诱导动力学曲线
Ziziphus jujuba
saline-alkali stress
physiological and biochemical indexes
chlorophyll fluorescence induction kinetic curve
