中文摘要：

【目的】研究低磷环境中,不同磷利用效率杉木家系幼苗生长特性与其叶片和根尖内源激素含量变化的相关性,为进一步揭示磷高效利用杉木基因型对低磷胁迫响应策略的内在调控机制提供参考依据。【方法】选择在缺磷环境下磷素利用效率较低的No.4与磷素利用效率较高的No.41杉木半同胞家系为研究对象,通过设计3个供磷水平（P0：不供磷,0 mmol·L^-1KH_2PO_4;P_1：低度供磷,0.5 mmol·L^-1KH_2PO_4;P_2：正常供磷,1.0mmol·L^-1KH_2PO_4）的室内沙培模拟试验,分别测定2个家系幼苗在不同供磷水平下的生长特性以及叶片与根系内细胞分裂素（ZT）、赤霉素（GA_3）、生长激素（IAA）和脱落酸（ABA）含量的变化。【结果】1）不供磷条件下,41号家系杉木幼苗根长、根表面积和根平均直径的增量以及根冠比均明显高于4号家系（P〈0.05）。2）低度供磷条件下,4号家系杉木幼苗叶片内ZT和IAA含量显著高于41号家系,而这2个家系杉木幼苗在不供磷条件下根系内ZT含量与正常供磷处理相比显著降低（P〈0.05）,IAA和ABA含量则显著增加（P〈0.05）,且41号家系杉木幼苗根系ABA含量显著高于4号家系的任意供磷水平（P〈0.05）。3）正常供磷条件下,2个家系叶片、根系内源激素含量与幼苗生长特性指标均无显著相关（P〉0.05）;低度供磷条件下,4号家系仅叶片IAA、GA_3含量与根长增量呈显著负相关（P〈0.05）,而41号家系叶片ZT含量与根长、根表面积增量呈显著正相关（P〈0.05）,苗高增量与IAA呈显著正相关（P〈0.05）,与ABA呈显著负相关（P〈0.05）;不供磷条件下4号家系叶片IAA含量与苗高增量呈极显著正相关（P〈0.01）,根系ABA含量与根长、根表面积和根平均直径呈显著负相关（P〈0.05）,而41号家系仅有根平均直径与ZT和GA_3呈一定的相关性（P〈0.05）;从根冠比来看,这2个家系在低度供磷和不供磷条?

英文摘要：

We investigated the relationship between the growth characteristics and the change of endogenous hormone contents in needles and root tips of Chinese fir（ Cunninghamia lanceolata） with different phosphorus（ P） use efficiencyunder lower P condition,to provide a basis for further understanding of the mechanism of responding to the P stress.【Method】Two half-sib families of Chinese fir（ No. 4 and No. 41,respectively with low and high P use efficiencies under no P supply condition） were treated with three different P levels（ P_1： no P supply,0 mmol·L~（-1）KH_2PO_4; P_2： low P supply,0. 5 mmol·L~（-1）KH_2PO_4; P_3： normal P supply,1. 0 mmol·L~（-1）KH_2PO_4） and cultured in sand medium indoor to investigate the growth of seedlings under different P levels,and the contents of cytokinins（ ZT）,gibberellins（ GA_3）,growth hormone（ IAA） and abscisic acid（ ABA） in needles and roots. 【Result】1） Under no P supply condition,the increments of the average length,surface area and diameter of roots,and the root to shoot ratio of family No. 41 were significantly higher than those of family No. 4（ P〈 0. 05）. 2） Under low P supply condition,the contents of ZT and IAA in the needles of family No. 4 were significantly higher than those of family No. 41; the content of ZT in roots of the two families were lower than those of normal P level（ P〈 0. 05）,but both of IAA and ABA contents were significantly increased; the content of ABA in family No. 41 seedlings roots was higher than that in family No. 4（ P〈 0. 05）. 3）Under normal P supply condition,there was no significant correlation between the contents of endogenous hormones and the growth characteristics of the seedlings. Under low P supply condition,the contents of IAA and GA_3 in family No. 4 both were negatively correlated with the root length increment（ P〈 0. 05）; for family No. 41,the content of ZT in needles was positively correlated with root length increment,like as root surface area increment?