Shan Chaoping, Shi Can, Liang Xinran, Zu Yanqun, Wang Jixiu, Li Bo, Chen Jianjun
College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China.
Plants (Basel). 2024 Sep 2;13(17):2457. doi: 10.3390/plants13172457.
Variations in the cadmium (Cd) accumulation and root characteristics of different genotypes of rice during three developmental periods of dry cultivation were investigated in pot experiments in which two levels of Cd were added to the soil (0 and 10 mg kg). The results show that the Cd concentration in each organ of the different rice genotypes decreased in both the order of roots > shoots > grains and during the three developmental periods in the order of the maturity stage > booting stage > tillering stage. The lowest bioaccumulation factor (BCF) and translocation factor (TF) were found in Yunjing37 (YJ37) under Cd stress. At maturity, Cd stress inhibited the root length of Dianheyou34 (DHY34) the most and that of Dianheyou 918 (DHY918) the least, also affecting the root volume of DHY34 and Dianheyou615 (DHY615) the most and that of YJ37 and Yiyou 673 (YY673) the least; the inhibition rates were 41.80, 5.09, 40.95, and 10.51%, respectively. The exodermis showed the greatest thickening in YY673 and the lowest thickening in DHY615, while the endodermis showed the opposite result. The rates of change were 16.48, 2.45, 5.10, and 8.49%, respectively. The stele diameter of DHY615 decreased the most, and that of YY673 decreased the least, while the secondary xylem area showed the opposite result; the rates of change were -21.50, -14.29, -5.86, and -26.35%, respectively. Under Cd stress treatment at maturity, iron plaque was extracted using the dithionite-citrate-bicarbonate (DCB) method. The concentration of iron (DCB-Fe) was highest in YJ37, and the concentration of cadmium (DCB-Cd) was lowest in DHY34. YJ37 was screened as a low Cd-accumulating variety. The concentration of available Cd in the rhizosphere soil, iron plaque, root morphology, and anatomy affect Cd accumulation in rice with genotypic differences. Our screening of Cd-accumulating rice varieties provides a basis for the dry cultivation of rice in areas with high background values of Cd in order to avoid the health risks of Cd intake.
通过盆栽试验，研究了旱作栽培三个发育时期不同基因型水稻在添加两种镉水平（0和10 mg/kg）土壤中的镉（Cd）积累和根系特征变化。结果表明，不同水稻基因型各器官中的镉浓度均表现为根＞茎＞籽粒，且在三个发育时期均表现为成熟期＞孕穗期＞分蘖期。在镉胁迫下，云粳37（YJ37）的生物富集系数（BCF）和转运系数（TF）最低。成熟期，镉胁迫对滇禾优34（DHY34）根长的抑制作用最大，对滇禾优918（DHY918）根长的抑制作用最小，对DHY34和滇禾优615（DHY615）根体积的影响最大，对YJ37和宜优673（YY673）根体积的影响最小；抑制率分别为41.80%、5.09%、40.95%和10.51%。外皮层在YY673中增厚最大，在DHY615中增厚最小，而内皮层则相反；变化率分别为16.48%、2.45%、5.10%和8.49%。DHY615的中柱直径减小最多，YY673的中柱直径减小最少，而次生木质部面积则相反；变化率分别为-21.50%、-14.29%、-5.86%和-26.35%。在成熟期镉胁迫处理下，采用连二亚硫酸盐-柠檬酸盐-碳酸氢盐（DCB）法提取铁膜。YJ37中铁（DCB-Fe）浓度最高，DHY34中镉（DCB-Cd）浓度最低。YJ37被筛选为低镉积累品种。根际土壤有效镉浓度、铁膜、根系形态和解剖结构影响水稻镉积累，存在基因型差异。我们对镉积累水稻品种的筛选为镉背景值高的地区进行水稻旱作提供了依据，以避免镉摄入带来的健康风险。
