Physiological and Nutritional Responses of Pear Seedlings to Nitrate Concentrations
Physiological and Nutritional Responses of Pear Seedlings to Nitrate Concentrations
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DOI：
10.3389/fpls.2018.01679
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发表时间：
2018-11-20
影响因子：
5.6
通讯作者：
Tao, Shutian
中科院分区：
文献类型：
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作者：
Chen, Guodong;Wang, Li;Tao, Shutian
氮(N)是植物生长的重要元素，适宜的氮素供应对果树的最佳产量至关重要。果树的氮肥施用往往过多，不仅造成环境污染，还会通过N毒性降低果树的产量。为评价不同浓度硝态氮对梨植株生长、根系形态性状及其他营养元素响应的影响，以5个水平的氮素处理梨苗（Pyrus betulifolia Bunge），缺氮和过量氮均抑制了梨砧木的生长发育。然而，在处理过的叶片和根之间观察到不同的可见症状。在缺氮条件下，叶片变黄，根系伸长受到刺激，硝酸盐还原酶活性和叶绿素含量下降。另一方面，在过量氮处理下，叶片呈深绿色，并伴有焦化，根系伸长受到抑制，硝酸盐还原酶活性和叶绿素含量下降。此外，硝酸盐处理不仅影响氮含量，还影响其他矿质营养素含量。综上所述，合理选择氮肥供应对保证梨树正常生长发育至关重要。
Nitrogen (N) is an important element for plant growth, and a suitable N supply is crucial to ensure optimal yields from fruit trees. Frequently, application of N fertilizers to fruit trees is often excessive, which not only leads to environmental pollution, but also reduces the output from fruit trees through N toxicity. To evaluate the effects of different concentrations of nitrate on plant growth, root-morphological traits, and other nutritional element's responses in pear, pear seedlings (Pyrus betulifolia Bunge) were treated with five levels of N. Both N-deficiency and an excess of N inhibited the growth and development of pear rootstocks. However, different visible symptoms were observed among treated leaves and roots. Leaf yellowing, the stimulation of root elongation, a decrease in nitrate reductase activity and chlorophyll content were observed under N-deficiency conditions. On the other hand, dark green leaves accompanied by coking, the suppression of root elongation, and a decrease in nitrate reductase activity and chlorophyll content were displayed under regimes of excess N. In addition, not only the N content, but also the content of other mineral nutrients was influenced by nitrate treatments. Taken together, these results suggested that a careful choice of N fertilizer supply is crucial to ensure normal growth and development in pear trees.