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设置3个水分梯度,即自然降水(W_1)、自然降水增加50%(W_2)和增加100%(W_3)以及4个施氮梯度,即模拟氮沉降添加0(N_1)、5(N_2)、10(N_3)和15(N_4)g N·m~(-2)·a~(-1),研究增加降水和氮添加对杨树幼苗非结构性碳水化合物(NSC)的影响.结果表明:增加降水和氮添加对杨树幼苗NSC含量具有显著的交互作用.随着降水的增加,N_1水平叶片和枝条可溶性糖含量不变,叶片、枝条、主干、粗根和细根淀粉含量下降;N_2和N_3水平各器官可溶性糖含量下降或保持不变,淀粉含量降低或先升高后降低;N_4水平各器官可溶性糖和淀粉含量升高或先降低后升高.随着氮沉降的增加,W_1处理叶片可溶性糖含量不变,淀粉含量增加,细根可溶性糖含量增加,淀粉含量不变;W_2处理各器官可溶性糖含量不变或先增加后减少,淀粉含量降低或先增加后降低;W_3处理各器官可溶性糖、淀粉和NSC含量均增加.各水分和施氮梯度处理下,杨树幼苗可溶性糖含量为39.1~88.3 mg·g~(-1),叶片中最高,细根中最低,淀粉含量为23.3~46.8 mg·g~(-1),粗根中最高,细根中最低.
Three water gradients, namely, natural precipitation (W_1), natural precipitation increase by 50% (W_2) and increase by 100% (W_3), and four nitrogen fertilization gradients, namely N 0, N 2, The effects of increasing precipitation and N addition on the non-structural carbohydrates (NSC) of poplar seedlings were studied under the conditions of 10 (N_3) and 15 (N_4) g N · m -2 · a -1 .The results showed that: Increased precipitation and N addition had a significant interaction on NSC content of poplar seedlings.With the increase of precipitation, the content of soluble sugar in leaves and branches remained unchanged at N_1 level, and the content of starch in leaves, branches, stems, coarse roots and fine roots decreased. N_2 And N_3 decreased or remained unchanged, while starch content decreased or increased first and then decreased; soluble sugar and starch content increased or decreased first and then increased with N_4 levels.With the increase of nitrogen deposition, W_1 The content of soluble sugar in the leaves increased, the content of soluble sugar in the fine roots increased, while the content of starch in the roots remained the same. The contents of soluble sugar in the organs increased or decreased at first, then decreased or increased first and then decreased. The content of soluble sugar, starch and NSC increased in all organs, and the water content and nitrogen fertilizer gradient Under the treatment, the soluble sugar content of poplar seedlings was 39.1-88.3 mg · g ~ (-1), the lowest in the leaves, the lowest in the fine roots, the starch content was 23.3 ~ 46.8 mg · g ~ (-1) , The lowest in fine roots.