Drought stress and re-watering increase secondary metabolites and enzyme activity in dendrobium moniliforme

Dendrobium moniliforme (Dendrobium moniliforme (L)Sw.) is a drought-tolerant crop, and it is a precious herbal and widely used as health care medicine and food around Asia. Drought stress can affect the growth and secondary metabolites of plants, thus, the current study was performed to investigate the changes on basic physiological processes and accumulation of secondary metabolite by drought and re-water in dendrobium moniliforme. Dendrobiurri moniliforme was grown in four kinds of drought intensity and was exposed for 20 days, then gave it a re-water operation in different stages (day 0,5,10,15,20). Results indicated that the leaf water content was significantly decreased under drought stress, and it was increased under the mild and moderate drought stress upon re-watering. And the carotenoids content was increased the most under severe drought stress, the total chlorophyll content at the early stage was increased under drought stress. The CAT (catalase) activity was decreased significantly and it was increased upon re-watering at the early stage of the drought stress. However, it did increase the polysaccharide, fiavonoids, and alkaloids contents in stems. Additionally, POD (peroxidase) activity and MDA (Malondialdehyde) content were significantly increased in leaves of dendrobium moniliforme under some treatments. These results demonstrate that dendrobium moniliforme can adapt to the drought stress by changing the physiology, and the secondary metabolites were improved under drought stress or re-watering. (C) 2016 Elsevier B.V. All rights reserved.