β–氨基丁酸对Cd胁迫下菊花生理特性的影响

Effects of β-aminobutyric Acid on Physiological Characteristics of Chrysanthemum Under Cd Stress

为探究β–氨基丁酸(BABA)能否缓解Cd胁迫对菊花生长和生理代谢的毒害作用,以耐Cd型菊花品种‘钟山金葵’和Cd敏感型菊花品种‘钟山丹桂’为试验材料,用1/2Hogland营养液培养,研究了200μmol·L-1 Cd单独处理和200μmol·L-1 Cd+0.2 mmol·L-1 BABA处理下两个品种的生长、生物量、Cd积累和转运、根尖Cd流量以及叶片MDA含量、相对电导率、叶绿素含量、脯氨酸含量的变化。结果表明:Cd胁迫抑制菊花的生长和叶绿素的合成,破坏细胞膜结构的完整性,引起膜脂过氧化伤害。耐Cd品种‘钟山金葵’的膜脂过氧化程度较低,细胞膜的完整性较好,能快速、大量地合成渗透调节物质(脯氨酸)来减轻Cd胁迫的毒害作用。BABA能改善Cd胁迫下菊花的生长,缓解Cd胁迫对株高、根长和生物量的抑制作用。BABA还可减缓Cd胁迫下叶片MDA含量的增加和相对电导率的升高,但并不增加脯氨酸的含量。耐Cd品种‘钟山金葵’根尖Cd离子流量大于Cd敏感型品种‘钟山丹桂’,能积累较多的Cd,并可以利用老叶贮存Cd,且受害程度较低。BABA能促进Cd胁迫下根系对Cd的吸收及其向地上部的转运,但对Cd在地上部不同叶位中的分布无影响。BABA处理可以促进菊花对Cd污染土壤的修复。

To illustrate whether the toxicity of cadmium to chrysanthemum on the growth and physiological metabolism could be reduced or not by exogenous β-aminobutyric acid（BABA）,chrysanthemum‘Zhongshan Jinkui＇（Cd tolerant）and‘Zhongshan Dangui＇（Cd sensitive）were subjected to hydroponic culture in 1/2Hogland nutrient solution supplemented with 200 μmol · L-1 Cd,200 μmol · L-1 Cd with 0.2 mmol · L-1 BABA. The morphology and biomass,Cd accumulation and transportation,Cd fluxes on root tip and relative electrolyte conductivity,contents of MDA,chlorophyll,proline in leaves were measured. The results showed that Cd stress inhibited the growth,biomass and chlorophyll synthesis,destroyed the integrity of the cell membrane,and induced membrane lipid peroxidation damage in both varieties. ‘Zhongshan Jinkui＇suffered less membrane lipid peroxidation,thereby showed better integrity of the cell membrane than‘Zhongshan Dangui＇,it could synthesis a large number of osmotic adjustment substances such as proline to alleviate the toxicity of Cd stress. BABA improved the growth,biomass of chrysanthemum under Cd stress. Meanwhile,BABA reduced the increase of MDA content and relative conductivity in leaves,but no increase in proline were observed with the presence of BABA. Cd tolerant variety‘Zhongshan Jinkui＇has a larger Cd fluxes than the Cd sensitive cultivar‘Zhongshan Dangui＇,the tolerant cultivar accumulated higher Cd than the sensitive one,especially in the base mature leaves. BABA accelerated the absorption of Cd in both varieties and promoted transportation of Cd from root to aboveground,but has no effect on distribution of Cd in different leaf positions,inferring application of BABA could contribute to the phytoremediating of cadmium contaminated soil by chrysanthemum.