马尾松二代无性系生长和针叶N/P化学计量特征

[目的]在土壤有效P匮乏的立地条件下,揭示针叶N、P含量及其化学计量比与马尾松生长性状的相关性。[方法]以马尾松二代育种群体内30个无性系为试验对象,野外调查11年生时马尾松二代无性系树高、胸径等生长性状与针叶N、P含量及其化学计量比的相关性。[结果]结果表明:(1)各生长性状在马尾松二代无性系间差异显著,且无性系重复力较高,均达到0.95以上。马尾松成熟针叶和当年生针叶N、P含量及N/P在二代无性系间差异均达显著水平;(2)相关分析表明,马尾松二代无性系树高、胸径与成熟针叶和当年生针叶N含量、N/P均呈显著或极显著正相关,与成熟针叶N/P的相关系数分别为0.608 6和0.542 8,与当年生针叶N/P的相关系数分别为0.515 9和0.679 2;(3)基于主要生长性状、针叶N和P含量及其化学计量比,可将30个马尾松二代无性系聚为4类:类群1无性系树高、胸径等生长表现优良,成熟针叶N/P较高,而当年生针叶N/P相对较低;类群2无性系树高、胸径等生长表现较好,成熟针叶和当年生针叶N/P值在30个无性系中居中间水平;类群3占试验无性系总数的一半,树高、胸径等生长表现一般,成熟针叶与当年生针叶N/P相差较大,大部分无性系成熟针叶N/P较低,而当年生针叶N/P相对较高;类群4树高、胸径等生长表现较差,成熟针叶和当年生针叶N/P均较低。[结论]在贫P立地下,马尾松二代亲本无性系C13(7750×1126)和C14(3201×1123)各生长指标均较高,可能是通过调整当年生针叶和成熟针叶的养分分配,增加了当年生针叶对限制其生长的P素的再利用和再吸收,促进了N素的吸收,调整了当年生针叶和成熟针叶的N/P,以形成特定的养分分配机制。

Plant Growth and Needles N and P Stoichiometric Characteristics of Second-generation Pinus massoniana Clones

[Objective] The purpose of this study is to reveal the correlation between stoichiometric characteristics of N, P and the growth traits of Pinus massoniana on P deficiency site. [Method] Taking 11-year-old P. massoniana clones in second-generation breeding population as test materials, the major growth traits, including height, DBH, and its correlation with N, P stoichiometric characteristics of needles, were studied through field investigation. [Result] (1) Significant differences were observed in traits among clones, and high clonal repeatability was detected. There were significant differences among clones in N, P content and N/P of mature and current year needle; (2) The major growth traits of clones had positive correlations with N content and N/P of mature and current year needle; (3) Based on major growth traits and N, P stoichiometric characteristics of needles, the 30 clones tested were clustered into 4 groups. Group 1 exhibited superior growth traits, with higher N/P of mature needle, but relatively lower N/P of current year needle. Group 2 exhibited good growth traits, with medium N/P of mature and current year needle. Group 3 had the ordinary growth traits, but this group accounted for half of the tested clones. The N/P of mature needle had larger difference with current year needle. Group 4 exhibited poor growth traits, while N/P of mature and current year needle were lower. [Conclusion] Two clones belonging to group 1 exhibited perfect growth traits, which might by adjusting N, P content and N/P of mature and current year needle to form a particular nutrient allocation mechanism.