以福建尤溪的天然米槠[Castanopsis carlesii (Hemsl.) Hayata]林乔木层、灌木层和草本层的26 个主要优势种为研究对象,分析了植物不同器官的C、N 和P 含量及其比值的差异及相关性,并对不同器官C、N 和P 含量在不同层次间的分布特征进行了研究。结果显示:同一器官中均为C 平均含量最高、P 平均含量最低;其中,叶片中C、N 和P 含量分别为344. 95 ~486. 15、6. 26 ~19. 50 和0. 18 ~0. 62 mg·g^-1 ,C/ N、C/ P 和N/ P 比分别为22. 52 ~61. 21、696. 64 ~2 589. 72 和11. 38 ~58. 94;根系中的C、N 和P 含量分别为277. 95 ~ 458. 30、1. 41 ~ 12. 73 和0. 13 ~ 0. 44mg·g-1 ,C/ N、C/ P 和N/ P 比分别为34. 63 ~296. 17、731. 45 ~3 372. 69 和8. 81 ~34. 41;乔木层和灌木层植物枝条中C、N 和P 含量分别为407. 75 ~473. 75、3. 10 ~7. 39 和0. 09 ~0. 61 mg·g^-1 ,C/ N、C/ P 和N/ P 比分别为57. 43 ~148. 15、776. 64 ~5 054. 44 和7. 05 ~48. 11;乔木层植物树干中的C、N 和P 含量分别为432. 56 ~ 463. 32、2. 67 ~6. 35 和0. 16 ~0. 31 mg·g^-1 ,C/ N、C/ P 和N/ P 比分别为68. 12 ~167. 73、1 494. 58 ~2 860. 63 和11. 35 ~29. 06。乔木层植物的不同器官按C 含量由高至低依次排序为叶片、枝条、树干、根系,按N 和P 含量由高至低依次排序为叶片、枝条、根系、树干;灌木层植物的C 含量在枝条中最高、根系中最低,N 和P 含量在叶片中最高、枝条中最低;而草本层植物地上部分的C、N 和P 含量均高于地下部分。除根系中的N 含量与P 含量呈极显著正相关外,同一器官的C、N 和P 含量间均无显著相关性,但与C/ N、C/ P 和N/ P 比值间大多有极显著的相关性。不同器官的C、N 和P 含量也因植物所处层次的不同而异,其中乔木层植物叶片中均最高、草本层植物叶片中均最低;乔木层植物全株的C 含量最高、N 含量最低,草本层植物全株的N 含量最高、C 含量最低,各层植物全株的P 含量比较接近。研究结果表明:尤溪天然米槠林内植物叶片的C、N 和P 含量均偏低,P 缺乏很可能是限制该林分植物生产力的最重要元素。

Taking twenty-six main dominant species in arbor, shrub and herb layers of Castanopsis carlesii (Hemsl.) Hayata natural forest in Youxi of Fujian Province as research objects, variation and correlation of C, N and P contents and their ratios in different organs of plants were analyzed, and distribution characteristics of their contents in different organs among different layers were also studied. The results show that in the same organ, C average content is the highest while P average content is the lowest. In which, contents of C, N and P in leaf are 344. 95-486. 15, 6. 26-19. 50 and 0. 18-0. 62 mg·g^-1, and ratios of C/ N, C/ P and N/ P are 22. 52-61. 21, 696. 64-2 589. 72 and 11. 38-58. 94, respectively; contents of C, N and P in root are 277. 95-458. 30, 1. 41-12. 73 and 0. 13-0. 44 mg·g^-1, and ratios of C/ N, C/ P and N/ P are 34. 63-296. 17, 731. 45-3 372. 69 and 8. 81-34. 41, respectively; contents of C, N and P in branch of plants in arbor and shrub layers are 407. 75-473. 75, 3. 10-7. 39 and 0. 09-0. 61 mg·g^-1, and ratios of C/ N, C/ P and N/ P are 57. 43-148. 15, 776. 64- 5 054. 44 and 7. 05-48. 11, respectively; and contents of C, N and P in trunk of plants in arbor layer are 432. 56-463. 32, 2. 67-6. 35 and 0. 16-0. 31 mg·g^-1, and ratios of C/ N, C/ P and N/ P are 68. 12-167. 73, 1 494. 58-2 860. 63 and 11. 35-29. 06, respectively. In different organs of arbor layer plants, the order of C content from high to low is leaf, branch, trunk, root, while that of N and P contents is leaf, branch, root, trunk. In shrub layer plants, C content is the highest in branch and the lowest in root, while N and P contents are the highest in leaf and the lowest in branch. In herb layer plants, contents of C, N and P in above-ground part are higher than those in under-ground part. Except having extremely significantly positive correlation between contents of N and P in root, correlations among contents of C, N and P in the same organ are unsignificant, but most correlations between their contents and ratios of C/ N, C/ P and N/ P are extremely significant. Contents of C, N and P in different organs are varied with different layers of plants, in which, those in leaf of plant in arbor layer are the highest, while those in herb layer are the lowest. And C content is the highest and N content is the lowest in whole plant of arbor layer, and N content is the highest and C content is the lowest in whole plant of herb layer, while P content in whole plant of different layers is close. It is suggested that contents of C, N and P in leaf of plants of C. carlesii natural forest in Youxi are lower and P deficiency is likely to the most important element for limiting productivity of this forest.