【摘要】 为了解施肥后树木体内非结构碳的变化规律,对黑龙江省尚志市小九林场15年生的水曲柳人工林进行氮磷混合施肥,氮肥设4个水平(N0:0 g/m~2,N1:5 g/m~2,N2:12.5 g/m~2,N3:20 g/m~2),磷肥设3个水平(P0:0 g/m~2,P1:7.5 g/m~2,P2:15 g/m~2),氮磷肥配施共计12个处理。于施肥后第3年进行叶片净光合速率、叶绿素、全氮、全磷,以及叶片和细根非结构碳质量分数等指标测定。结果表明:氮磷施肥处理导致水曲柳叶片净光合速率、叶绿素a、叶绿素b和总叶绿素质量分数增加,并在N3P0、N3P1、N1P2、N2P2和N3P2处理显著高于对照。叶片淀粉和总非结构性碳(Non-structural carbohydratem, NSC)质量分数也高于对照,并在N1P1、N2P1、N3P1、N1P2、N2P2和N3P2处理与对照差异显著;细根淀粉和NSC质量分数均表现出随施氮量增加逐渐降低的趋势,但与对照无显著差异。随施氮量增加,叶片氮质量分数逐渐增大,施氮也促进了磷的吸收,所有施肥处理叶片磷质量分数均高于对照。叶片氮质量分数与叶片净光合速率、叶绿素、淀粉和总NSC质量分数均显著正相关,而叶片磷质量分数仅与叶片净光合速率和总NSC质量分数显著正相关。上述结果说明,氮磷施肥通过改善叶片氮素质量分数促进净光合速率,进而引起了叶片NSC蓄积量的增加,但土壤供氮条件的改善却导致NSC向细根的分配降低。更多还原

【Abstract】 To understand the changes of NSC in trees after fertilization, the 15-year-old Fraxinus mandshurica plantation was selected for nitrogen and phosphorus addition in Xiaojiu Forest Farm in Shangzhi City, Heilongjiang Province. The nitrogen and phosphate fertilizer was set at 4 levels(N0:0 g/m~2, N1:5 g/m~2, N2:12.5 g/m~2, N3:20 g/m~2), and 3 levels(P0:0 g/m~2, P1:7.5 g/m~2, P2:15 g/m~2) respectively. There was a total of 12 treatments of combined application of nitrogen and phosphate fertilizers. The net photosynthetic rate, chlorophyll, total nitrogen, total phosphorus, and non-structural carbohydrate(NSC) concentration of leaves and fine roots were measured at the 3 rd year after fertilization. The results showed that: N and P fertilization led to an increase in the net photosynthetic rate and concentrations of chlorophyll a, chlorophyll b and total chlorophyll of F. mandshurica leaves, and the treatments of N3 P0, N3 P1, N1 P2, N2 P2 and N3 P2 were significantly higher than that of the control. After fertilization, starch and total NSC concentration of leaves were also higher than that of the control, and the treatments of N1 P1, N2 P1, N3 P1, N1 P2, N2 P2 and N3 P2 were significantly higher than those in the control. After fertilization, starch and total NSC concentrations of fine root gradually decreased with the increase of N application, but there was no significant difference from the control. With the increase of nitrogen addition, the leaf nitrogen concentration gradually increased, and N application also promoted the absorption of P, resulting the leaf P concentration of all fertilization treatments was higher than that of the control. N concentration of leaves was positively correlated with the net photosynthetic rate, chlorophyll, starch and total NSC concentration of leaves significantly, while P concentration of leaves was only positively correlated with the net photosynthetic rate and total NSC concentration of leaves significantly. Our results indicate that N and P fertilization could promoted the net photosynthetic rate by improving the N concentration in leaves, which resulted in the increase of NSC in leaves, but the allocation of NSC to fine roots decreased with the improvement of soil N supply.更多还原