不同硝铵配比对杜梨幼苗生长和生理特性的影响

摘要：梨是我国重要果树，但不合理的施肥常会导致梨树营养失衡以及果品品质下降。因此，了解果树的营养需求对于梨产业的可持续发展具有重要意义。本研究以杜梨幼苗为试材，在水培条件下研究了不同硝铵配比(1:0, N1; 3:1, N2; 1:1, N3; 1:3, N4; 0:1, N5)对杜梨幼苗生长和生理特性的影响。结果表明，在N2处理条件下，植株长势最好，其株高、茎粗、地上部鲜重、叶面积显著高于其他处理，叶片的叶绿素含量、硝酸还原酶(NR)活性亦显著高于其他处理。此外，N2处理植株叶片的可溶性糖、脯氨酸(Pro)等渗透调节物质产生较少，丙二醛(MDA)含量较低，而超氧化物歧化酶(SOD)活性相对较高。综上所述，营养液中硝铵配比为3:1时，杜梨幼苗受胁迫程度最低，生长和生理状况最佳。该研究可为梨园氮肥的合理施用提供基础数据。

Effect of different nitrate and ammonium ratios on growth and physiological characteristics of Pyrus betulaefolia seedlings

Abstract: Pear is an important fruit tree in China, however, unreasonable fertilization often leads to nutrition imbalances and the decrease of fruit quality. Therefore, understanding the nutrition demand of fruit tree have important significance for the sustainable development of the pear industry .The effects of different ratios of nitrate to ammonium (1:0, N1; 3:1, N2; 1:1, N3; 1:3, N4; 0:1, N5) on growth and physiological characteristics in leaves of Pyrus betulaefolia seedlings under hydroponic conditions were studied. The results indicated that the optimal conditions for the growth of Pyrus betulaefolia was N2 treatment, with higher plant height, stem diameter, shoot FM and leaf area. And also, the higher chlorophyll content and nitrate reductase (NR) activity of leaves were also shown in N2 treatment. In addition, the soluble sugar, proline (Pro) and malondialdehyde (MDA) content of leaves of N2 treatment were relatively lower, while the activity of superoxide dismutase (SOD) was relatively higher. Overall, when the ratio of nitrate to ammonium was 3:1, the degree of stress of seedlings was minimum, and the growth and physiological characteristics were optimal. This study will provide theoretical basis for reasonable use of nitrogen fertilization in pear orchard.