生境变化对栓皮栎幼苗营养元素含量的影响

以栓皮栎在我国天然分布的南界、中部和北界为研究样点,将不同纬度的栓皮栎实生幼苗移栽到同一地点,于生长旺季同时在种源地和移栽地进行取样和测定,探讨生境变化对栓皮栎幼苗生长旺季营养元素含量特征的影响.结果表明:生境变化对栓皮栎幼苗各器官N含量和茎P含量的影响显著,而对各器官K含量和叶片、根P含量影响较小；在种源地,栓皮栎各器官的N含量与纬度间呈极显著的正相关,茎、根的全P含量随纬度升高而降低,叶片N/P的变化不明显；移栽后,北界栓皮栎幼苗各器官的N、P含量显著降低,不同纬度来源对栓皮栎幼苗N、P含量的影响更为明显；各纬度栓皮栎叶片的N/P均有不同程度的升高.不同纬度栓皮栎幼苗不同器官的营养元素含量存在差异,其对生境变化的响应也不相同.

Effects of habitat change on nutrient contents in Quercus variabilis seedlings

Quercus variabilis seedlings were collected from the habitats at different latitudes, and transplanted on the same experimental sites installed in the central part and southern and northern boundaries of China, where Q. variabilis has a natural distribution, aimed to study the effects of habitat change on the nutrient contents in the seedlings in their vigorous growth period. With habitat change, the various organs nitrogen (N) content and the stem phosphorous (P) content of the transplanted seedlings changed significantly, but the organs potassium (K) content and the leaf- and root P content had less change. In the experimental sites, the organ N content of the transplanted seedlings had significant positive correlation with the latitudes where the seedlings grew, the stem- and root P contents decreased with the increasing latitude, while the leaf N:P ratio had less change. The organ N and P contents of the transplanted seedlings growing in northern boundary decreased significantly, and the effect of the latitudes was more obvious. The leaf N:P ratio of all the seedlings transplanted from different altitudes increased to different degrees. It was concluded that the nutrient contents in different organs of Q. variabilis seedlings varied with latitude, and the seedlings had different responses to habitat change.