【摘要】 为了解耐镉（Cd）能力不同的小麦品种幼苗对镉适应性的生理差异,分别用浓度为0、10、50、100和300μmol/L的Cd处理河农6425（Cd敏感型）和92R137（耐Cd型）的幼苗,测量2个小麦品种幼苗的生长指标、含水量、叶绿素荧光参数等,并检测根部Ca²⁺水平的变化.结果表明,与对照组相比,Cd处理组中2个小麦品种幼苗的株高、叶长、最长根长以及含水量等生长指标均下降,地上部位和根部的Cd含量显著升高. 92R137的长势和含水量好于河农6425,Cd含量和转移吸收均高于河农6425.低浓度Cd处理组中,2个小麦品种的叶绿素荧光参数F_v/F_m、F_v/F₀、YⅡ和qP的变化幅度均较小,高浓度Cd处理组中,YⅡ和qP随着处理浓度的增加和培养时间的延长急剧下降,且河农6425的变化幅度高于92R137的变化幅度.正常小麦根尖有少量Ca²⁺均匀分布,随Cd处理时间延长,小麦根尖Ca²⁺水平逐渐上升,积累于分生区. 92R137小麦根尖的Ca²⁺水平随时间匀速增加,荧光亮度逐渐增强;河农6425小麦根尖的Ca²⁺积累速率逐渐加快,Cd处理20 min时Ca²⁺水平明显高于92R137.总之,Cd适应性强的品种92R137幼苗的长势好,含水量、Cd含量、Cd转移系数和叶绿素荧光参数均高于Cd适应性差的品种河农6425,根尖中Ca²⁺水平低于后者的水平.更多还原

【Abstract】 In order to learn the physiological difference of adaptation between wheat cultivars with different tolerance to cadmium（Cd）stress,Henong 6425（Cd-sensitive genotype）and 92R137（Cd-tolerant genotype）were used as experimental materials to investigate the effect of various Cd concentrations（0,10,50,100 and 300 μmol/L） on wheat seedlings. The measurement items contained growth indexes,water content,chlorophyll fluorescence parameters and Ca²⁺ level in root tip. The results showed that the plant height,leaf length,the longest root length,water content of the seedlings in the Cd treatment groups all decreased compared with those of the control group. While Cd content both of shoots and roots significantly increased.The growth and water content in 92R137 were better than those in Henong 6425. Cd content,Cd absorption and transport in 92R137 were higher than those in Henong 6425. In the Cd treatment groups with low Cd concentration,the change range of chlorophyll fluorescence parameters F_v/F_m,F_v/F₀,YⅡ and qP of two cultivars were rather small. In the Cd treatment groups with high Cd concentration,the Y Ⅱ and qP in 92R137 and Henong 6425 both decreased significantly with increase of the Cd concentration and the Cd treatment time,and the change range in Henong 6425 was higher than that in 92R137. There was a small amount of Ca²⁺ evenly distributed in the normal wheat root tip. With the prolongation of Cd treatment time,the Ca²⁺ accumulation gradually increased and accumulated in the root meristematic zone. The Ca²⁺ level in the root tip of 92R137 increased uniformly within the period of Cd t reatment,and the fluorescence intensity increased gradually. The accumulation rate of Ca²⁺in Henong 6425 increased gradually,and the Ca²⁺level was significantly higher than that of 92R137 after Cd stress for 20 min. On the whole,the growth,water content,Cd content,Cd transport coefficient and chlorophyll fluorescence parameters in 92R137 were all higher than those in Henong 6425,and the Ca²⁺ level in the root tips in 92R137 was lower than that in Henong 6425.更多还原