毛竹林爆发式生长期立竹器官营养成分的动态变化

Nutritional elements in organs of a Phyllostachys edulis stand during its fast growth period

为了探讨毛竹Phyllostachys edulis爆发式生长与营养物质积累的关系,在毛竹爆发式生长期的4,5,6月中旬分别采集不同年龄(1,3,5年生)立竹器官(叶、枝、秆、鞭)样品,测定氮、磷、钾、钙和镁质量分数,分析不同年龄立竹间差异。结果表明:在毛竹爆发式生长期,相同年龄立竹叶、枝、秆、鞭中的养分质量分数存在差异,氮、磷、钾、钙和镁质量分数竹叶中最高,平均分别为23.18,2.51,12.28,4.08,和0.96 g·kg-1;竹鞭次之,竹秆中最低;氮、磷、钾质量分数竹叶4月较低,5月和6月较高,而在竹枝、竹秆、竹鞭中则是4月较高,5月和6月较低;不同年龄立竹相同器官的营养元素质量分数也存在差异,且不同营养元素的动态变化规律亦不相同。在显著水平为0.05的条件下,4月,叶、枝、秆中氮、磷、钾质量分数1年生立竹高于3年生和5年生立竹;5月,竹叶中钾质量分数随竹龄增加而减少,叶、鞭中氮质量分数1年生和3年生立竹显著高于5年生立竹;6月,竹叶中氮和磷质量分数1年生立竹显著低于3年生和5年生立竹,竹鞭中氮和磷质量分数1年生立竹显著高于3年生和5年生立竹;5-6月,不同年龄立竹叶、枝、秆中镁质量分数均差异不显著。研究表明:毛竹在爆发式生长期立竹器官营养物质存在明显的生理整合作用。

To explain the relationship between the explosive growth of Phyllostachys edulis and nutrition accu- mulation, samples of different aged （1-, 3-, and 5-year old） Ph. edulis and their organs （leaf, branch, stem, and rhizome ） were collected in April, May and June from Lin＇an County, Zhejiang Province in eastern China. The content of N, P, K, Ca, and Mg were studied to determine any discrepancies among the different ages. Re- sults showed that the average nutritional content for leaves （in g＂ kg-1） of the same age during the fast growth period were N, 23.18; P, 2.51; K, 12.28; Ca, 4.08; and Mg, 0.96 with leaves being higher, in turn, than rhi- zomes, branches, and stems. During the fast growth period, N, P, and K concentrations in leaves were higher in April than in May and June; whereas branch, stem, and rhizome concentrations in April were lower than in May and June. Nutrient content in the same organ for different aged plants varied by month. In April, N, P, and K in leaves, branches, and stems were significantly greater （P 〈 0.05） in 1-year old stands than 3- and 5-year old; in May, as bamboo age increased, K in leaves significantly decreased （P 〈 0.05）, but N in 1- and 3-year old leaves was significantly greater （P 〈 0.05） than 5-year old; in June, N and P in 1-year old leaves were significantly less （P 〈 0.05） than 5- and 5-year old, but in rhizomes were significantly greater （P 〈 0.05）. From May to June, among different ages, Mg in leaves, branches, and stems was not significantly different （P 〉 0.05）. This study indicated that in different organs of Ph. edulis, nutrients existed physiological integration of the fast growth period. [Ch, 4 tab. 15 ref.]