多效唑对不同立地条件下黄荆生长及生理特征的影响

该试验以绿化卷材为基质材料,对沙场、渣场和混凝土屋面3种立地条件下生长的黄荆进行不同浓度(0、100、200、300、400mg·L~(-1))多效唑处理,研究根施多效唑对黄荆生长和生理特征的影响以及不同立地环境的应用差异。结果显示:(1)随多效唑浓度升高,3种立地类型黄荆株高和生物量呈降低趋势,冠幅、基径、叶面积、根幅、主根长和主根径呈减小趋势,叶片长宽比和根冠比表现出增大的趋势;多效唑处理使黄荆叶片相对含水量、叶绿素含量、可溶性糖和可溶性蛋白含量增加,使丙二醛含量下降。(2)不同立地条件下黄荆对多效唑处理的表现具有一定差异,隶属函数法综合评价显示,对沙场、渣场和屋面3种立地类型的黄荆生长调控效果最佳的多效唑浓度分别为400mg·L~(-1)、300mg·L~(-1)、100mg·L~(-1)。(3)当多效唑浓度在渣场和屋面分别为400、300mg·L~(-1)时,黄荆叶片开始受到伤害,对多效唑的耐受阈值表现为沙场渣场屋面。研究认为,多效唑可有效调控黄荆的形态和生物量分配,增强细胞渗透调节和抗氧化损伤能力,从而提高黄荆的抗逆性和环境适应性,但在应用时应考虑不同立地背景的差异,因地制宜地选择使用浓度和用量,使其更好地应用于人工植被恢复与建设。

Effects of Paclobutrazol on Growth and Physiological Characteristics of Vitex negundo L. under Different Site Conditions

With the Greening Roll as matrix material, we investigated the growth and physiological characteristics of Vitex negundo growing on the sand land, slag yard and concrete roof to clarify the mechanism responsive to paclobutrazol treatment with different concentrations (0, 100, 200, 300 and 400 mg·L^-1 paclobutrazol). The results showed that: (1) the height and biomass of plant decreased, as well as basal diameter, crown, leaf area, root range, taproot length and taproot diameter, while the leaf length to width ratio and root shoot ratio increased. The leaf relative water contents, chlorophyll contents, soluble sugar and soluble protein contents increased after paclobutrazol treatment. And malondialdehyde (MDA) contents decreased. (2) The growth and physiological responses of V. negundo to paclobutrazol treatment under three site conditions were significantly different. The comprehensive evaluation of indices by membership function method indicated that the appropriate paclobutrazol concentrations of sand land, slag yard and concrete roof were 400 mg·L^-1, 300 mg·L^-1 and 100 mg·L^-1, respectively. (3) When the paclobutrazol concentration of slag yard and concrete roof reached 400 mg·L^-1 and 300 mg·L^-1 respectively, the plants had gotten hurt. The tolerance threshold for paclobutrazol of plants on sand land was higher than that on slag yard and concrete roof. The study indicated that paclobutrazol could enhance stress resistance and environment adaptability of V. negundo by regulating plant morphology, adjusting biomass allocation, improving the osmotic adjustment and antioxidant activities. The differences of site conditions should be considered to utilize the paclobutrazol better and safely with the appropriate concentration and dosage in artificial vegetation restoration and construction.