长筒石蒜生物量构成和养分质量分数季节动态

Seasonal Changes of Biomass Allocation and Micronutrient Contents in Lycoris longituba

对长筒石蒜(Lycoris longituba)鳞茎、根、地上部分各月份的生物量构成,N、P、K质量分数和总量分配动态变化以及叶片养分再吸率进行了研究。结果表明,叶生物量最高占29.6%,花果生物量最高占37.0%,二者生物量变动格式呈单峰型;鳞茎生物量占总生物量的57.9%～96.3%,变动格式呈双底型;根占3.1%～8.6%,变动格式呈单底型;叶生长期间,根系生物量所占比率呈线性减少,叶枯后开始增加,秋季为高速生长期。地上部分、鳞茎和根系N、P、K年平均质量分数分别为25.8、5.1、14.5 g.kg-1,15.6、3.8、8.9 g.kg-1和27.6、5.1、18.5 g.kg-1。鳞茎年平均质量分数w(N):w(P):w(K)=4:1:2。开花结实N、P、K消耗量分别为28.4%、36.6%、46.2%。叶片N、P、K回收率分别为46.7%、49.6%、63.4%。长筒石蒜在养分、碳、水循环中具有较为独特的转移、转化机制,使该植物对环境条件的胁迫具有较好的适应能力。

Monthly distribution of biomass and nutrients （N, P, K） in the abovegreund part, bulb and root of Lycoris Iongituba was studied to probe the nutrient mechanism in L. longituba. The nutrient resorption efficiency in leaves was determined. Results showed that the variation in biomass of leaves and floral organ can be expressed as a unimodal curve. The maxi- mum biomass of leaves and floral organ accounted for 29.6% and 37.0% of the total biomass, respectively. The bulb bio- mass occupied 57.9% -96.3%, and the variation exhibited a double-valley curve. The root biomass accounted for 3.1% - 8.6%, and the variation can be described as a single-valley curve. The root biomass decreased linearly at leaf growth stage, then began to rise after leaf withering, and it exhibited the highest growth rate until fall. The annual average contents of N, P and K were 25.8, 5.1, 14.5 g· kg^-1 for the aboveground part, and 15.6, 3.8, 8.9 g ·kg^-1 for bulb and 27.6, 5.1, 18.5 g · kg-1 for roots. The nutrient ratio of N, P, and K in bulb was 4 ： 1 ： 2. The rates of consumption of N, P and K for reproduction were 28.4%, 36.6% and 46.2% of respective nutrient biomass, respectively. Resorption effieiencies of N, P and K in leaves were 46.7%, 49.6% and 63.4%, respectively. It indicates that the distinct ecological mechanism in retranslocation and conversion of nutrients, earbon and water in L. longituba makes it more adapted to environmental stresses.