Control of leaf expansion in sunflower (Helianthus annuus L.) by nitrogen nutrition.
Control of leaf expansion in sunflower (Helianthus annuus L.) by nitrogen nutrition.
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DOI：
10.1093/jxb/47.3.359
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发表时间：
1996-03
影响因子：
6.9
通讯作者：
S. Palmer;D. Berridge;A. McDonald;W. Davies
中科院分区：
文献类型：
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作者：
S. Palmer;D. Berridge;A. McDonald;W. Davies
向日葵幼苗最初以较高的相对硝酸盐供应率（0.27 mol N mol N–1 d–1）生长。随后供应量降低至较低水平（0.04 mol N mol N–1 d–1）。叶面积发育对硝酸盐有效性突然下降的响应的特征是随着初级和次级叶对的扩展。硝酸盐供应下降的时间是当初生叶对表皮的细胞分裂基本完成时。减少硝酸盐的利用率对叶面积扩张有很大影响。主叶对的最终叶片大小受到影响，表明硝酸盐可用性对细胞扩张的影响。到实验结束时，次生叶对的面积仅为对照幼苗的三分之一。通过使用微型细胞压力探针直接测量来评估表皮细胞膨胀压力在这种生长反应中的作用。没有检测到硝酸盐可用性降低后细胞膨胀压降低。结论是，膨胀压的降低并不是叶面积扩张减少的原因，并且表明细胞扩张减少是由于细胞壁特性的变化。随着硝酸盐有效性的减少，叶和根脱落酸的浓度增加。
Seedlings of Helianthus annuus L. were grown at an initially high relative nitrate supply rate (0.27 mol N mol N–1 d–1). The supply was subsequently reduced to a low rate (0.04 mol N mol N–1 d–1). The response of leaf area development to this abrupt decrease in nitrate availability was characterized by following the expansion of the primary and secondary leaf pairs. The timing of the drop in nitrate supply was when cell division in the epidermis of the primary leaf pair was largely complete. Reducing the availability of nitrate had a strong effect on leaf area expansion. The final leaf size of the primary leaf pair was affected indicating an effect of nitrate availability on cell expansion. By the end of the experiment the secondary leaf pair was only one-third the area of that on control seedlings. The role of epidermal cell turgor pressure in this growth response was assessed by direct measurements with a miniature cell pressure probe. No reduction in cell turgor pressure following the decrease in nitrate availability was detected. It is concluded that a reduction in turgor pressure was not responsible for the reduction in leaf area expansion and it is suggested that reduced cell expansion was due to changes in cell wall properties. Concentrations of leaf and root abscisic acid increased following the reduction in nitrate availability.