镉胁迫对3个水稻品种(系)根系生长及有机酸和氨基酸分泌的影响

Effect of cadmium stress on root growth and organic acids and amino acid secretion of three rice varieties

以水稻亲本蜀恢498、Ⅱ–32A和杂交稻Ⅱ优498为试材,通过营养液培养试验,研究不同镉胁迫时间(7、14 d)和不同质量浓度(0、0.5、1.0、3.0 mg/L,0为CK)Cd Cl2处理下的水稻根系生长情况以及根系有机酸和氨基酸的分泌特征。结果表明:与对照相比,在镉胁迫7 d和14 d时,各质量浓度的Cd Cl2处理下3个水稻品种(系)的根系干重减轻,根系总数变少,根系表面积和根系体积变小,根系总长变短,且对根系总数、根系总长、根系表面积等的影响达显著水平;当镉胁迫7 d和14 d时,蜀恢498、Ⅱ–32A和Ⅱ优498分泌的有机酸和氨基酸含量均随Cd Cl2质量浓度的增加呈先增加后减少的趋势,都在Cd Cl2质量浓度为0.5 mg/L时达最大,胁迫7 d时,3个品种(系)的有机酸含量分别为3.44、3.31和3.43 mg/g,氨基酸含量分别为41.07、42.03和40.53μg/g,胁迫14 d时,3个品种的有机酸含量分别为3.40、3.38和3.33 mg/g,氨基酸含量分别为34.95、35.95和35.28μg/g,各处理与对照相比,差异均达显著水平;分泌的有机酸组分中以草酸含量较高,其次是苹果酸;分泌的氨基酸组分中甘氨酸含量相对较高,其次是丝氨酸和苏氨酸;品种(系)间比较,在镉胁迫7 d和14 d,Cd Cl2质量浓度为0.5 mg/L时,3个品种(系)根系分泌的有机酸和氨基酸含量差异没有统计学意义,而在中浓度(1.0 mg/L)和高浓度(3.0 mg/L)镉胁迫下Ⅱ优498分泌有机酸和氨基酸含量显著高于其亲本蜀恢498和II–32A。

In this study, three rice varieties of Shuhui498, II–32A and hybrid rice IIyou498 were chosen as the experimental materials to investigate the root growth and organic acids and amino acid secretion under two periods of cadmium stress（7 and 14 d） with three cadmium concentrations（0.5, 1.0 and 3.0 mg/L of Cd Cl2, 0 as control）. The results showed that： In the day of 7th and 14 th under cadmium stress, compared to the control, all treatments of Cd Cl2 decreased in the indexes of root dry weight, total root number, root surface area, root volume and root length. The difference between the cadmium streatments and the control in total root number, root length and root surface area were at significant level; when in 7 d of cadmium stresses, the contents of organic acid of three varieties were 3.44, 3.31 and 3.43 mg/g, the amino acid of three varieties were 41.07, 42.03 and 40.53 μg/g, respectively. while in 14 d of cadmium stresses, the contents of organic acid of three varieties were 3.40, 3.38, 3.33 mg/g, the amino acid of three varieties were 34.95, 35.95 and 35.28 μg/g, respectively. The difference between the Cd Cl2 treatments and the control reached significant level in the contents of organic acid and amino acid of three rice varieties. The content of oxalic acid was higher than malic acid in the component of organic acid secreted, The content of glycine in the secretory component was relatively high, the second were the serine and threonine. Comparison between varieties（or lines）, in 7 d and 14 d of cadmium stress with 0.5 mg/L Cd Cl2, the contents of organic acids and amino acid were not significant difference among the three rice varieties, while IIyou498 was significantly higher than Shuhui498 and II–32A under the cadmium stress with 1.0 and 3.0 mg/L Cd Cl2.