Zinc-Induced Changes in Growth Characters,Foliar Properties,and Zn-Accumulation Capacity of Pigeon Pea at Different Stages of Plant Growth

Application of zinc (Zn) [50, 100, 200, 300, and 400 μ g zinc sulfate (ZnSO₄)/g of soil] reduced the foliage and the total growth of pigeon pea [Cajanus cajan (Linn.) Huth]. The root-shoot length ratio, varying little with age, was relatively low in the treated plants. Decrease in dry weights of stem and root was more pronounced in the late stages of plant development. The root-shoot dry weight ratio, maximum in the flowering stage, was lower in treated plants than in the control. Number of pods per plant declined, showing a positive correlation with Zn concentration. Net photosynthetic rate, declining with plant age, was significantly low in the treated plants. Density and size of stomata and trichomes, stomatal conductance, intercellular carbon dioxide concentration, quantity of green pigments, nitrate reductase activity, and the nitrate and protein contents in the leaves also declined significantly. Proportion of vascular tissues both in stems and roots increased with plant age with a concomitant reduction of pith and cortex. Under zinc stress, the relative proportion of tissues varied inconsistently. Dimensions of vessel elements and fibers in stems and roots, increasing with the plant age, were always smaller in the treated plants. The vulnerability factor and mesomorphic ratio of treated plants declined, suggesting induction of water stress due to zinc treatments. Accumulation of Zn^{2 +} in different plant parts was considerably high at each developmental stage of the treated plants, and showed a positive correlation with Zn in the soil.     

处理竹类植物紫外阻隔纤维的新方法

目前粘胶纤维的生产方法主要用于将竹加工成工业纺织纤维中。然而,粘胶方法中使用了大量的化学制剂,因此这个过程对环境保护不利。这个过程也不能保留竹子固有的独特性能,如紫外线(UV)筛选和抗菌功能。因此,有必要设计一个有效和更环保的生产方法,这也将保留以竹类植物为原料的生产纤维的独特性能。在本研究中,采用了新方法对竹子进行加工,涉及的热机械处理,如超声处理、震动筛磨和连续搅拌沸腾。氢氧化钠,过氧化氢、酶制剂和水在这一过程中分别得到了采用,并对其再纤维加工的产生的影响进行了比较。本研究也对竹子加工前后的形态和紫外线屏蔽能力进行了分析。结果表明,竹子可以只通过水和球磨而不需要使用任何有害化学物质就能被加工纤维。使用轻度酸水解和双氧水下超声波的组合处理是能够有效的分离纤维,并提供更好的纤维外观。