中文摘要：

以盆栽耐盐碱芦荟‘不夜城’幼苗为材料,采用不同浓度Na2CO3溶液（不同渗透势）处理芦荟幼苗7 d后,测定其叶片叶绿体保护酶超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸氧化酶（APX）、谷胱甘肽转移酶（GST）活性以及叶绿素、丙二醛（MDA）、渗透调节物质含量和电解质外渗率等的变化,以探讨芦荟抵抗盐碱胁迫伤害的机制。结果显示：当溶液渗透势较高时（大于-7.19×10^5Pa）,Na2CO3胁迫下的芦荟幼苗叶片叶绿体保护酶活性都呈显著上升趋势,而叶绿素含量、可溶性蛋白、MDA含量以及电解质外渗率却无明显变化;在溶液渗透势较低时（小于-7.19×10^5Pa）,Na2CO3胁迫下芦荟幼苗的渗透调节物质含量显著增高,叶绿体保护酶活性特别是叶绿素含量显著下降,而MDA含量和电解质外渗率却呈上升的趋势。研究表明：一定浓度的Na2CO3胁迫下,芦荟幼苗可以通过提高自身叶绿体保护酶的活性来降低活性氧的积累量,同时提高渗透调节能力来增强其抗逆性;但在过高浓度的盐碱胁迫下,过高的Na＋浓度和pH也会对芦荟幼苗叶片造成一定的氧化伤害。

英文摘要：

The mechanics about anti-injury in Aloe nobilis seedlings against saline-alkali stress were investigated in present research.When A.nobilis seedlings were suffered from Na2CO3 stress in different concentrations for 7 d,the activities of superoxide dismutase（SOD）,catalase（CAT）,ascorbate peroxidase（APX）,glutathione transferase（GST）,the contents of chlorophyll,malonaldehyde（MDA） and osmotica in leaves of A.nobilis seedlings,the electrolyte leakage rate were determined.When the osmotica potential in media was comparatively higher（higher than-7.19×105 Pa）,an increasing trend was observed in activities of protective enzymes in leaves of A.nobilis seedlings,but no changes in chlorophyll content,MDA content and electrolyte leakage rate.Whereas,when osmotic potential in media was further decreased（lower than-7.19×105 Pa）,the osmotica contents increased along with increasing MDA content and electrolyte leakage rate in A.nobilis seedlings,but decreased in the protective enzymes and chlorophyll contents.This suggested that under Na2CO3 stress in a suitable concentration,the accumulation of active oxygen was decreased through enhancing the protective enzymes activities.Meanwhile,the ability of osmotica could enhance the stress-resistance of seedlings.However,under higher salt-alkali stress,A.nobilis seedlings would also be injured due to redundant Na＋ and over high pH.