摘要
采用野外调查取样和实验室分析相结合的方法,以陕西太白和甘肃小陇山5年（5a）,10年（10a）,20年（20a）生华北落叶松为试验材料,分析林下土壤全氮、全磷含量,林木根、茎、叶的生物量和全氮、全磷含量,根系形态特征,以及它们之间的相关性.结果显示：（1）不同林龄华北落叶松土壤全氮含量随土层深度的增加而降低,而土壤全磷含量并未表现出均一规律,0～60 cm土层中的全氮、全磷含量之间呈显著正相关关系.（2）叶中的氮磷含量最高,且叶和细根中的氮磷含量显著高于粗根和茎中的含量,各器官内氮磷含量存在显著正相关关系.（3）各器官生物量和氮磷积累量随着林龄的增加而显著增加,茎的生物量最大,叶中氮磷积累量最高.（4）表层土壤（0～20cm）氮含量和细根氮、磷含量均与细根比根长存在显著正相关关系.（5）粗根总长、侧根平均长、最大径向距离和最大根深随林龄的增加而增加;粗根氮、磷含量分别与粗根总长、粗根最大径向距离呈显著负相关关系.研究表明：土壤氮含量的适当提高,可以增加细根比根长,当粗根氮磷含量下降时,华北落叶松通过拓展根系吸收氮磷养分的范围来满足自身生长的需要.
Using samplings from different aged Larix principis-rupprechtii Mayr.plantations located in Taibai Mountain,Shaanxi and Xiaolong Mountain,Gansu of China,respectively,we analyzed total nitrogen （N）,total phosphorus（P） in soil,root,stem and leaf tissues,plant biomass,root characteristics and their correlations.The results showed that：（1）N concentrations in soil decreased with increases in soil depth in different aged Larix plantations,but P concentrations in soil did not display such a pattern.Significantly positive linear correlations were found between N and P concentrations in 0-60 cm soil.（2）N and P concentrations in leaves were the highest among all plant tissues.N and P concentrations in leaves and fine roots were significantly higher than those in coarse roots and stems.Significantly positive linear correla tions were detected between N and P concentrations in all plant tissues.（3）Biomass and accumulated N and P amount in different plant tissues increased with increases in ages of plantations.Biomass of stem and accumulated N and P amount in leaves were higher than those of other tissues.（4）There were positive linear correlations between specific root lengths,and N concentrations in 0 20 cm soils,N and P concentrations in fine roots.（5）Total length of coarse roots,mean length of proximal roots,maximum radial distance and maximum root depth increased with increases in ages of plantations.Negative linear correlations were found between concentrations of N and P in coarse roots and lengths of coarse roots,and maximum radial distances of coarse roots.Those results indicated that,specific root lengths increased with an appropriate increase about N concentrations in 0 20 cm soils,when N and P concentrations in coarse roots down,the roots will extend outward to increase the range of absorption of N and P nutrients in order to meet the normal growth of the Larix plantations.
出处
《西北植物学报》
CAS
CSCD
北大核心
2014年第7期1432-1442,共11页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家重点基础研究发展计划("973")项目(2012CB416902)
国家林业局公益性行业科研专项(201204210)
教育部高等学校博士学科点专项科研基金课题(20130204110012)
关键词
华北落叶松
根系特征
氮
磷
Larix principis-rupprechtii Mayr.
root characteristics
nitrogen
phosphorus
