湿地松针叶功能性状及其对磷添加的响应

目的 揭示湿地松人工林针叶功能性状间的关系,探讨针叶功能性状对磷添加的响应及对环境养分的适应策略。方法 以12年生湿地松人工林为研究对象,设置3个磷元素梯度(P1为25 kg/hm², P2为50 kg/hm², P3为100 kg/hm²)和不施磷为对照(CK)共4个处理,分析不同处理下叶长、叶面积和比叶面积等9个形态指标与针叶全氮、全磷和有机碳等养分含量的变化,探讨针叶形态指标与养分含量的相关性。结果①各处理下湿地松针叶各功能性状的变异系数为6.62%~19.77%,其中叶鞘长和比叶面积的变异系数大,均高于19%,有机碳含量变异系数最小,仅为6.61%。②与CK相比,随着施磷浓度的增加,除针叶干物质含量显著降低外(P<0.05),针叶叶面积、比叶面积及养分含量等指标均上升。③湿地松针叶的叶面积和比叶面积与全钾和全磷间存在显著正相关(P<0.05),相关系数达0.597以上,而针叶干物质含量与全磷、全钾和有机碳含量间表现出显著负相关(P<0.05),相关系数分别为-0.840、-0.639和-0.530。结论①湿地松针叶功能性状均属较弱变异,在特定环境中湿地松针叶功能性状具有较强的内稳性;②磷添加可以影响湿地松针叶的形态特征和养分储量,高浓度磷添加(P3)的效果最明显。③湿地松针叶形态建成与其养分含量相关,养分含量高促进针叶生长代谢、叶面积增加,同时加快干物质含量向其他器官转运,使针叶干物质含量减少。

Responses of needle functional traits of Pinus elliottii to phosphorus addition

【Objective】 The aim of this study is to reveal the correlation between functional traits of needles in middle-aged Pinus elliottii plantations and to explore the response mechanism of functional traits of needles to the phosphorus addition and the adaptation strategy to environmental nutrients. 【Method】 In this study, a 12-year-old P. elliottii plantation was selected as the research object. Three phosphorus gradients (P1 as 25 kg/hm ², P2 as 50 kg/hm², P3 as 100 kg/hm²) and no phosphorus application (CK) were used as controls. The changes in nine morphological indexes, such as leaf length, leaf area and specific leaf area, and the contents of total nitrogen, total phosphorus, and organic matter in needles were analyzed. 【Result】 ① The coefficient of variation of functional traits of P. elliottii needles under all treatments ranged from 6.62% to 19.77%, among which the coefficient of variation of sheath length and specific leaf area was larger than 19%, and the coefficient of variation of organic carbon was the least (6.61%). ② Compared with CK, the increase in P concentration, except in the dry matter content of needles, decreased significantly (P < 0.05), while other morphological indices such as leaf area, specific leaf area and nutrient content of needles increased. ③ There was a close correlation between morphological indices and the nutrient content of P. elliottii needles. The leaf area and specific leaf area of P. elliottii needles were positively correlated with the contents of total K and total P (P < 0.05), and the correlation coefficient was above 0.597. The dry matter content of P. elliottii needles was negatively correlated with the contents of total P, total K and organic matter (P < 0.05), with correlation coefficients of -0.840, -0.639, and -0.530, respectively. 【Conclusion】 ① The functional traits of P. elliottii needles were weakly variable, and the functional traits of P. elliottii needles had strong internal stability in specific environments. ② Phosphorus supplementation could improve the morphogenesis and nutrient storage of P. elliottii needles, and the effect of high concentration (P3) phosphorus supplementation was the most obvious. ③ The morphogenesis of P. elliottii needles is related to their nutrient content. High nutrient content promotes the growth and metabolism of needles, increases the area of needles, and speeds up the transport of dry matter to other organs, which reduces the dry matter content of needles.