تاثیر محلول پاشی اسید هیومیک بر گیاه دارویی صبرزرد در خاک‌های آلوده با کادمیم

Cadmium (Cd) pollution is a major environmental and human health threat. Therefore there is a need for cost-effective remediation procedures. Chelators such as humic acid have shown positive effects in enhancing resistance to various stresses. The objective of this research was to investigate the use of humic acids at cadmium-contaminated soil on growth and soluble sugar concentration of aloe vera (Aloe vera L.). The experimental design was factorial with three cadmium levels: 0 (control), 4 and 6 mg kg-1 of soil, and four levels of humic acid spraying including 0, 0.5, 1.5 and 3 g lit-1. The experiment was conducted in 2012 at the Zabol University greenhouse. Cadmium contamination at 4 mg kg-1 increased quantitative traits and did not interfere with plant growth. However, 6 mg Cd kg-1 decreased fresh and dry weight of root and shoot, leaf length, leaf thickness, gel weight and plant height. In addition, toxic dosage of Cd (6 mg kg-1) increased soluble sugars of glucose, mannose and xylose. Application of humic acid had no effect on root length, root dry weight and soluble sugars of glucose, mannose and xylose. However, due to its positive impact on fresh and dry weight of shoot and some morphological characteristics, the humic acid spraying was recommended, but more research is needed.