不同类型甘薯茎和叶中碳、氮、磷化学计量学特征研究

选取3个鲜食型、3个淀粉型和3个紫甘薯品种,于不同生育期采集地上部茎、叶样品,测定其碳（C）、氮（N）、磷（P）含量,研究不同类型甘薯C、N、P生态化学计量学特征及其随生育期的变化规律。结果表明,甘薯叶中C、N、P含量范围分别为391~399、26.3~29.1、2.90~3.10mg/g,茎中分别为421~428、11.6~15.2、4.99~5.77mg/g,其在茎、叶中的差异大于甘薯类型间的差异;茎中C含量随生育期延长略有增加,但茎、叶中N和P含量则随生育期延长而降低,茎、叶中C、N、P含量随生育时期的变化大于甘薯类型间的变化。不同类型甘薯叶中C/N、C/P分别以紫甘薯和淀粉型甘薯最大,说明紫甘薯和淀粉型甘薯有较高的碳同化能力;3种类型甘薯叶中N/P为8.57~9.97,表明N元素是甘薯茎叶生长的主要限制因子。

Ecological Stoichiometric Characteristics of Carbon,Nitrogen and Phosphorus in Leaves and Stems of Different Types of Sweet Potato

Total of 9 sweet potato varieties were selected and were divided into 3 types i.e. fresh sweet potato, starch sweet potato, and purple sweet potato. The contents of carbon (C), nitrogen (N) and phosphorus (P) in the shoots and leaves were measured at different growth periods, to study the C, N, P ecological stoichiometric characteristics of different types of sweet potatoes and their changes with the growth period. The results showed that the content ranges of C, N, and P were 391-399, 26.3-29.1, 2.90-3.10mg/g in leaves, and 421-428, 11.6-15.2, and 4.99-5.77mg/g in stems, respectively. The differences in stems and leaves are greater than those in sweet potato types; the C content in the stems increases slightly with the growth period, but the content of other elements in the stems and leaves decreases with the growth period. The change of C, N and P contents in stems with growth period is greater than that among varieties. Purple sweet potato and starch sweet potato had the highest C/N and C/P respectively in leaves of different sweet potato varieties, which indicated that they had high C assimilation ability. The N/P values in three types of sweet potato leaves ranged from 8.57 to 9.97 which indicated that N was the main limiting factor of growth in sweet potato.