丝栗栲、苦槠和青冈幼苗叶片功能性状对增温和施氮的响应1）

摘要

通过MSR－2420红外辐射增温装置和人工氮输入，设置出增温和不同施氮梯度，研究了中亚热带常绿阔叶林的主要优势树种丝栗栲（Castanopsis fargesii）、苦槠（C．sclerophylla）和青冈（Cyclobalanopsis glauca）幼苗叶片干质量面积、叶氮质量分数、叶氮面积质量和叶片干质量与饱和鲜质量比4个功能性状指标对增温、施氮及其交互作用的响应。结果表明：增温导致增温区平均空气温度增加了1．22℃，平均空气相对湿度降低了7．07％，5、20 cm处平均土壤温度分别增加了1．05、0．65℃，土壤平均体积含水量分别降低了7．02％、5．52％。增温导致丝栗栲、苦槠和青冈幼苗叶片干质量面积、叶氮质量分数降低，干质量与饱和鲜质量比增加。施氮引起丝栗栲、苦槠和青冈幼苗叶片叶氮质量分数、叶氮面积质量和干质量与饱和鲜质量比增加，干质量面积降低。3种植物干质量面积、叶氮质量分数、叶氮面积质量和干质量与饱和鲜质量比对增温和施氮交互作用的响应趋势不同。增温和施氮交互作用对丝栗栲叶片干质量面积的影响程度大于单独增温和单独施氮，对苦槠叶片干质量面积的影响与单独施氮基本一致，而对青冈叶片干质量面积则没有明显影响。3种植物叶片叶氮质量分数对增温和施氮交互作用、单独施氮的响应基本一致。苦槠叶片叶氮面积质量对增温和施氮交互作用、单独施氮的响应相似，丝栗栲表现为交互作用大于单独施氮，并且WN2大于WN1，青冈则是交互作用小于单独施氮，并且WN2大于WN1。增温和施氮交互作用均导致3种植物叶片的干质量与饱和鲜质量比增加。%Through MSR-2420 infrared radiation warming devices and nitrogen fertilizer addition , we set up warming and differ-ent nitrogen fertilizer application level to investigate the effects of the warming , nitrogen fertilizer and their interaction on specific leaf area , leaf nitrogen content per unit mass , leaf nitrogen content per unit area and leaf dry matter content of Castanopsis fargesii, Castanopsis sclerophylla and Cyclobalanopsis glauca seedings, the dominant species of evergreen broad-leaved forest in the mid-subtropical zone.From January 2012 to January 2013, the mean air temperature, the mean soil temperature at 5 cm and 20 cm depths were enhanced by 1.22℃, 1.05℃and 0.65℃.However, the mean air relative humidity, the mean soil volume water content at 5 cm and 20 cm depths were 7.07%, 7.02%and 5.52%lower than that in the control area , respectively .In the condition of warming , the leaf dry matter content was higher than that of the control area, while the specific leaf area and leaf nitrogen content per unit mass were opposite .The nitrogen addition led to the in-crease of leaf nitrogen content per unit mass , leaf nitrogen content per unit area and leaf dry matter content and the de-crease of specific leaf area .The specific leaf area , leaf nitrogen content per unit mass , leaf nitrogen content per unit area and leaf dry matter content responses of Castanopsis fargesii, Castanopsis sclerophylla and Cyclobalanopsis glauca to war-ming and nitrogen interaction were different .The independent effect of warming and nitrogen on the specific leaf area of Castanopsis fargesii was lower than that of their interactions , and the interactions on the specific leaf area of Castanopsis sclerophylla were similar to the independent nitrogen, but there was no significant effect on the specific leaf area of Castan-opsis fargesii.The response of three seedlings leaf nitrogen content per unit mass to warming and nitrogen was basically con -sistent irrespective of the effects of their independent and interactive .The independent and interactive effects of warming and nitrogen to the leaf nitrogen content per unit area of Castanopsis sclerophylla were similar.The effects of warming and nitrogen interaction to leaf nitrogen content per unit area of Castanopsis fargesii was higher than that of the independent ni-trogen, and the effect of WN1 was lower than that of WN2.For the corresponding results of Cyclobalanopsis glauca, war-ming and nitrogen interaction effect was lower than the independent nitrogen , and the effect of WN 2 was higher than that of WN1.The interaction of warming and nitrogen caused the leaf dry matter content rise for three seedling leaves .