渗透胁迫下大白菜吸收转运~(45)Ca_(2 )的变化

在－０．３Ｐａ和－１．０ＰａＰＥＧ胁迫过程中，大白菜幼苗根系膜透性，ＴＴＣ还原能力和丙二醛含量的变化显示根受到的不同程度伤害．渗透胁迫处理下，根系对钙的吸收速率在［Ｃａ２＋］＞０．７５ｍｍｏｌ／Ｌ时明显受到抑制．根系对４５Ｃａ２＋的积累能力分别在－０．３ＰａＰＥＧ胁迫５ｈ和－１．０ＰａＰＥＧ胁迫３ｈ后受到抑制．而且大白菜各器官（根、茎、叶）对４５Ｃａ２＋的吸收、转运能力在渗透胁迫下发生不同程度下降．其中叶对渗透胁迫反映最敏感．胁迫条件下，叶片各部位４５Ｃａ２＋积累明显减少．其中叶缘反映最为敏感．

Changes of 45 Ca 2 uptake and translocation in Chinese cabbage at osmotic stress

Seedlings of Chinese cabbage were grown in the greenhouse at -0 3 Pa and -1 0 Pa PEG Membrane leakage, TTC reduction activity and MDA content of the roots were determined from one hour through ten hours after treatment as indexes of root injury Ca 2 uptake rate as a function of external Ca 2 ] at -0 3 Pa and -1 0 Pa PEG was much lower than the control when the external Ca 2 ] was more than 0 75 mmol/L 45 Ca 2 uptake was significantly inhibited at 3 hours after exposed to -1 0 Pa and at 5 hours after exposed to -0 3 Pa, respectively Distribution of 45 Ca 2 in roots, stems and leaves that young leaves are the most sensitive part to osmotic stress in terms of the absorption of Ca 2 , thus Ca deficiency occurs in young leaf margin when exposed to osmotic stress