论文部分内容阅读
在人工气候室水培条件下,对19份水稻核心种质和5份水稻品种的幼苗耐镉特性和镉离子(Cd~(2+))吸收动力学特性进行了研究,试验结果表明,水稻幼苗的根系生物量和镉含量都存在广泛的遗传差异。在0~4.45μmol·L~(-1)的外界环境中,不同基因型水稻幼苗根系的Cd~(2+)吸收动力学特征都符合米氏方程,但特征值F_(max)和K_m在基因型间有明显差异。F_(max)最小为37.8nmol·g~(-1)(DW)·h~(-1),最大为87.5 nmol·g~(-1)(DW)·h~(-1)。当根系F_(max)值高于55.5 nmol·g~(-1)(DW)·h~(-1)时,地上部的Cd~(2+)积累动力学特征也符合米氏方程;但当根系F_(max)值小于50.8 nmol·g~(-1)(DW)·h~(-1)时,地上部的Cd~(2+)积累动力学特征却符合线性方程,此时截距a与K_m值有密切关系,K_m值为0.5~1.3μmol·L~(-1)时a为正,K_m值为2.9~3.9μmol·L~(-1)时a为负。在4.45μmol·L~(-1)的Cd胁迫环境下,根系和地上部的Cd积累量与米氏方程的F_(max)和线性方程的斜率b表现出显著的线性相关。Cd转运效率既与环境中的Cd~(2+)浓度有关,也与地上部的Cd积累特性有关。地上部Cd积累特性符合线性方程的水稻品种,其转运效率随着环境中Cd~(2+)浓度的增加而持续升高,而地上部Cd积累特性符合米氏方程的水稻品种,其转运效率往往随着环境中Cd~(2+)浓度的升高而降低。这些结果说明水稻根系和地上部对Cd~(2+)的吸收存在不同的阻控机制,Cd~(2+)吸收特性和转运效率在基因型间有丰富的遗传多样性。根系F_(max)小且地上部线性方程斜率b也小的基因型多为根系Cd积累量低和Cd转运率低的低积累种质资源。
Under the conditions of hydroponics in the artificial climate chamber, the cadmium-tolerant characteristics and cadmium-ion (Cd 2+) uptake kinetics of 19 core rice varieties and 5 rice cultivars were studied. The results showed that rice Seedlings have a wide range of genetic differences in root biomass and cadmium content. In the external environment of 0-4.4μmol·L -1, the Cd 2+ absorption kinetics of rice seedlings with different genotypes all fit the Mie equation, but the characteristic values F max and K m were in the range of Significant differences between genotypes. The minimum F max was 37.8 nmol · g -1 DW and · h -1, and the maximum was 87.5 nmol · g -1 (DW) · h -1. When the F_ (max) value of the root system was higher than 55.5 nmol · g -1 (DW) · h -1, Cd 2+ accumulation kinetics in the shoots also accorded with the Mie equation. However, When the F max of the root system was less than 50.8 nmol · g -1 DW DW · h -1, the Cd 2+ accumulation kinetics in the shoots was in accordance with the linear equation There is a close relationship between a and K_m. When K_m is 0.5 ~ 1.3μmol·L -1, a is positive and a is negative when K_m is 2.9 ~ 3.9μmol·L -1. Under Cd stress of 4.45μmol·L -1, Cd accumulation in roots and shoots showed a significant linear correlation with the F max of the Mie equation and the slope b of the linear equation. Cd transport efficiency not only with the environment of Cd ~ (2 +) concentration, but also with the aboveground Cd accumulation characteristics. The Cd accumulation characteristics in above-ground part were in line with the linear equation of rice varieties, and the translocation efficiency continued to increase with the increase of Cd 2+ concentration in the environment, whereas the Cd accumulation characteristics in aboveground part accorded with Mie equation. The translocation efficiency Often with the environment Cd ~ (2+) concentration decreased. These results indicated that there existed different resistance mechanisms of Cd 2+ uptake in root and shoot of rice. Cd 2+ absorption and transport efficiency had rich genetic diversity among genotypes. Most of the genotypes with small F_ (max) roots and small slope b of the linear equations aboveground were mostly low-germplasm resources with low Cd accumulation and low Cd translocation.