Effects of Magnesium Stress on Growth,Distribution of Several Mineral Elements and Leaf Ultrastructure of‘Harumi’Tangor
Effects of Magnesium Stress on Growth,Distribution of Several Mineral Elements and Leaf Ultrastructure of‘Harumi’Tangor
复制标题
DOI：
--
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Yang Hui
中科院分区：
文献类型：
--
作者：
Yang Hui
研究了镁胁迫对春海橘生理响应和解剖特征的影响。网花C. sinenesis）]嫁接在香橙（C.在砂基质上，以24 mg. L-1为对照，240 mg. L-1为过量，其余3个为低镁处理，分别在营养液中添加0、2. 4、12、24和240 mg. L-1镁。结果表明，镁胁迫（无论是低镁还是高镁）均显著降低了水稻株高、根长、根系活力、叶片叶绿素含量和各部位干物质质量，但诱导了叶片相对电导率和MDA含量的增加。不施Mg（0 mg·L-1Mg2+）处理的影响更为明显，叶片抗氧化酶（SOD和CAT）活性也随之下降。随着外部Mg浓度的增加，植株各部位Mg浓度均显著增加，Mg在叶片中积累较多，其中上部幼叶Mg浓度高于基部老叶（过量Mg条件下除外）。Mg胁迫处理下，植株各组织中Zn含量均出现不同程度的下降，其中以低Mg（2.4mg·L-1）处理下下降最为明显。除2.4 mg·L-1 Mg外，硼（B）和钙（Ca）含量均为基部老叶高于上部嫩叶，过量Mg降低了上部和基部叶片的硼和钙含量。根据叶片结构和叶绿体超微结构的解剖观察，缺镁胁迫不仅导致叶绿体解体（叶绿体基质外观变暗，类囊体膜体积减少），而且还导致线粒体等其他细胞器的解体（膜模糊、体积减少和异常黑点）。过量Mg处理也使线粒体膜模糊，但叶绿体片层消失，淀粉粒和质体小体数量增多，体积增大。
To investigate the effects of magnesium(Mg)stress on physiological responses and anatomical characteristics of‘Harumi’tangor [Citrus reticulate ×(C. reticulata × C. sinenesis)] plants grafted on Xiangcheng(C. junos)rootstock,Mg at five levels(0,2.4,12,24 and 240 mg · L-1)in nutrient solution was exogenously supplied to the plants grown at sand medium,in which 24 and 240 mg · L-1 were considered as control and excess treatments,respectively,and the other three were treated as low Mg. Our results showed that,Mg stress(either under low or excess conditions)significantly decreased plant height,root length,root viability,leaf chlorophyll content as well as dry mass in various parts,whereas it induced leaf relative conductivity and MDA content. The effects were more pronounced in plants supplied without Mg(0 mg · L-1Mg2+ treatment),while the activities of antioxidant enzymes(SOD and CAT)in leaves declined synchronously. Mg concentration in all plant parts increased significantly as external Mg concentration increased,and it was found that compared to the other tissues,Mg tended to be accumulated more in leaves,where upper younger leaves had higher Mg concentrations than those in basal old leaves(except under excess Mg conditions). Zn concentration showed various degrees of decreases in various tissues of plants under Mg stress treatments,especially under the low Mg treatment 2.4 mg · L-1. Moreover,concentrations of boron(B)and calcium(Ca)were higher in basal old leaves than those in upper young leaves with the exception of 2.4 mg · L-1Mg,and excess Mg decreased those concentrations in leaves of either upper or basal parts. According to the anatomical observation in leaf structure and chloroplast ultrastructure,Mg deficiency stress resulted not only in the disorganization of chloroplsts(in a darker appearance of chloroplast stroma and a reduced volume of thylakoid membranes),but also of the other organelles like the mitochondria having blurred membranes with reduced volume and abnormal black spots). Excess Mg treatment also caused the mitochondria having blurred membranes,however,it led to disappearance of chloroplast lamellar,increment of the number and enlargement of the volume of starch grains and plastoglobulus.