基于短周期矮林模式的外源激素提高杜仲胶产量的效果

Efficacy of exogenous hormones in enhancing Eucommia rubber production from an Eucommia ulmoides short-rotation coppice

通过对比外源激素提高杜仲短周期矮林地上部分生物量和杜仲胶产量的效果,筛选出合适的外源激素种类及其田间施用质量浓度,为杜仲胶资源林培育提供技术支撑。以1年生栽植密度为66 666株·hm^(-2)的杜仲短周期密植矮林为对象,采用芸苔素内酯和赤霉素2种外源激素,按完全随机区组设计,通过比较杜仲叶和皮内杜仲胶含量的变化,苗木生长特性以及叶、皮、茎秆等地上部分生物量指标,分析施用外源激素对杜仲胶产量产生的作用效果。结果表明:(1)赤霉素显著促进苗高生长,但对其它指标的增效作用不明显。(2)经质量浓度为1 mg·L^(-1)和5 mg·L^(-1)的芸苔素内酯处理后,杜仲叶片内杜仲胶含量达到了4.74%、5.01%,分别是对照的3.21和3.04倍;苗高分别较对照增加了12.26%和16.09%;平均单株叶片数分别均比对照多8片;单株叶片质量分别是对照的2.21和2.25倍;单株树皮质量分别是对照的1.97和2.05倍;叶片生物量为2 993.54和3 089.83 kg·hm^(-2),树皮生物量为576.87和543.78 kg·hm^(-2),茎杆生物量为2 060.71和1 935.24 kg·hm^(-2),分别是对照的2.16和2.23倍、2.00和1.89倍、2.07和1.94倍。按平均含胶量计算,单位面积杜仲胶产量分别达到了167.28和182.90 kg·hm^(-2),分别为对照的4.58和5.01倍。(3)芸苔素内酯通过提高叶片胶含量、苗高生长量、单株叶片数、单株叶、皮、杆干质量等综合效应,在第一个采伐期即表现出极显著提高高密度杜仲矮林生物量和杜仲胶产量的效果。

The objectives of this study were to compare the aboveground biomass and Eucommia rubber production from a Eucommia ulmoides Oliver short-rotation coppice treated by exogenous hormones in the first rotation. The optimal hormone and its concentration was then determined for field applications. One-year-old E. ulmoides seedling was used for establishing a short-rotation coppice plantation in density of 66 666 stems hm-2. Completely randomized block design was applied to study the effects of the brassinolide and gibberellin on Eucommia rubber content in leaf and bark, growth characteristics and aboveground biomass. The results indicated that gibberellin had significant influence on height growth, while it had limited effect on rubber content and biomass increments. Rubber content in E. ulmoides leaf treated by 1 mg·L-1 and 5 mg·L-1 of brassinolide was 4.75% and 5.01%, 204% and 221% higher than that of the Control, respectively. Meanwhile, stem height increased by 12.26% and 16.09% and the number of leaves per plant was 8 and 12 leaves more as comparison to Control, respectively. The total leaf weight per plant were enhanced by 121% and 125%, the total bark weight per plant treated with 1 mg·L-1 and 5 mg·L-1 brassinolide were increased by 105% and 97% as comparison to control, respectively. Biomass of E. ulmoides leaf, bark and stake was 2 993.54 kg·hm-2 and 3 089.83 kg·hm-2, 567.87 kg·hm-2 and 543.78 kg·hm-2, 2 060.71 kg·hm-2 and 1 935.24 kg·hm-2 treated by 1 mg·L-1 and 5 mg·L-1 brassinolide; 116% and 123%, 100% and 89%, 107% and 94% higher than that of the Control, respectively. Total Eucommia rubber production was 167.28 kg·hm-2 and 182.90 kg·hm-2, 358% and 401% higher than that of the Control, respectively. The aboveground biomass and Eucommia rubber production was increased significantly in the first rotation of a E. ulmoides high density short-rotation coppice plantation by application of brassinolide through enhancing rubber content in leaf, stem height growth, the number of leaves and leaf or bark or stalk weight per plant.