Effects of cadmium on the uptake, distribution and assimilation of nitrate in Pisum sativum
Effects of cadmium on the uptake, distribution and assimilation of nitrate in Pisum sativum
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DOI：
10.1023/a:1004252816355
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发表时间：
1997-02-01
期刊：
影响因子：
4.9
通讯作者：
CarpenaRuiz, R
中科院分区：
文献类型：
--
作者：
Hernandez, LE;Garate, A;CarpenaRuiz, R
研究了豌豆植物中 NO3- 的净吸收、分布和同化情况，这些豌豆植物接受长期连续镉处理 10 天（10 或 50 μM Cd）或用 50 μM Cd 短期处理（72 小时）。在后一种处理中，还研究了将植物转移到无镉营养液中 96 小时“恢复期”的效果。所有这些处理都与“对照”（未接受镉的植物）进行比较。在这两个实验中，随着镉浓度的增加，鲜重的减少与地上部和根部水分含量（%）以及蒸腾速率的降低有关。芽和汁液中 NO3- 的浓度急剧下降，NO3- 净吸收受到严重抑制，其影响与芽硝酸还原酶 (NR) 活性的丧失有关。在短期Cd处理中，24小时后NO3-净吸收几乎完全受到抑制，但在将植物转移到无Cd营养液中后恢复。同样，观察到芽 NR 活性急剧下降。还研究了 K 的吸收、分布和组织分配，K 被认为是 NO3- 的主要抗衡离子。从 NO3-/K 吸收比率推断，钾吸收同样受到 Cd 的影响，该比率约为 10%。 10. 在长期和短期金属供应中，地上部的 K/NO3- 组织含量比值随着 Cd 的增加而增加。这些参数显示出与 NO3- 观察到的相似的 K 趋势，尽管其相对组织分布不受 Cd 的影响。
The net uptake, distribution and assimilation of NO3- were studied in pea plants subjected to either long-term continuous Cd treatment for 10 d (10 or 50 mu M Cd) or short-term treatment (72 h) with 50 mu M Cd In the latter treatment, the effects of transferring the plants to a Cd-free nutrient solution for a 'recovery period' of 96 h were also studied. All these treatments were compared with 'controls', plants which received no Cd. In both experiments, the reduction in fresh weight was associated with a decrease in the content (%) of shoot and root water and in transpiration rate as Cd concentration increased. The concentration of NO3- in the shoots and sap decreased dramatically and net NO3- uptake was severely inhibited, effects associated with a loss of shoot nitrate reductase (NR) activity. In the short-term Cd treatment, net NO3- uptake was almost completely inhibited after 24 h, but recovered after the transfer of plants to a Cd-free nutrient solution. Similarly, a dramatic decrease in the shoot NR activity was observed. The uptake, distribution and tissue partitioning of K was also studied, which is considered to be the major counterion of NO3-. Potassium uptake was similarly affected by Cd, as inferred from the ratio NO3-/K uptake, which was ca. 10. The ratio K/NO3- tissue content increased in the shoot concomitantly to Cd in both long-term and short-term metal supply. These parameters showed a tendency of K similar to that observed for NO3-, although its relative tissue distribution was not affected by Cd.