甘肃景电灌区不同栽植年限枸杞生物量分配特征

Biomass allocation characteristics of different-aged Lycium barbarum in Jintai electrical irrigation area,Gansu Province of Northwest China

枸杞(Lycium barbarum L.)常作为我国干旱区盐渍化土地开发利用中的首选灌木型经济林,研究枸杞各构件及根系生物量的分配特征可以为提高枸杞生产力及资源的持续利用提供理论依据。在甘肃景电灌区选择栽植4年、7年和11年的枸杞,研究枸杞枝条、果实、叶片生物量在垂直空间上的分布特征,并按地下根系径级的大小,研究了根系生物量在各径级的分配规律。结果表明:枸杞栽植初期植株间高度、冠幅差异较小,栽植7年进入生长旺盛期后差异较大,而栽植11年个体间形态指标差异又减小。栽植4年、7年、11年的枸杞总生物量及枝条生物量在50～100cm空间最大,而栽植4年的果实及叶片生物量最大值在50～100cm空间,栽植7年时果实及叶片生物量最大值在100～150cm空间。4年生与7年生枸杞粗根和细根生物量所占的比例均比较大,11年生时细根的生物量比例明显减小,而粗根的比例则超过了50%。果实与叶片以及中根与粗根的生物量均随栽植年限的增加而增加,但枝条以及细根和极细根的生物量为7年生>11年生>4年生。用二次函数可以较好地预测该区域枸杞叶片及地下根系各径级生物量与生长年限之间的关系。

Lycium barbarum L. is the top choice cash shrub planted on the saline soils in arid areas of China. To study the morphology and biomass allocation of L. barbarum could provide theoretical basis for enhancing the productivity of this shrub and supporting its sustainable use. In this paper, the L. barbarum plants of 4-, 7-, and 11-year old in the Jintai electrical irrigation area of Gansu were selected to study the biomass allocation in their branches, fruits, leaves, and different diameter sizes roots. Little variation was observed in the plant height and canopy diameter among the 4-year-old plants, greater variation was found among the 7-year-old plants （the vigorous growth stage）, and little variation was observed again among the 11-year-old plants. Vertically, the total biomass and branch biomass of the 4-, 7-, and 11-year old plants were the greatest at the 50-100 cm layer, the fruit and leaf biomass of the 4-year old plants were the greatest at the 50-100 cm layer, whereas the fruit and leaf biomass of 7-year-old plants were the greatest at the 100-150 cm layer. The biomass of the thick and thin roots of the 4- and 7-yearold plants occupied a greater proportion, while the biomass of the thick roots of the 11-year-old plants occupied over 50% but the biomass of the thin roots only had a small proportion. The biomass allocation to the fruits, leaves, and medium and coarse roots increased with plant age, whereas the biomass allocation to the fine roots was the greatest for the 7-year-old plants, followed by the 11-year-old plants, and then the 4-year-old plants. A quadratic function was developed to describe the relationships between the leaf and root biomass and the plant age.