The Seed Germination and Seedling Physiological Characteristics of Prinsepia utilis under Drought Stress

PurposeTo understand the drought tolerance of Prinsepia utilis.

MethodsDifferent volume fractions (0, 5%, 10%, 15%, 20% and 25%) of polyethylene glycol (PEG-6000) were used to simulate the effects of drought stress on the seed germination, and different volume fractions (0, 10%, 20%, and 30%) of PEG-6000 were used to simulate the effect of drought stress on the physiological characteristics of the seedling growth.

Results(1) Under the stress of 5% and 10% PEG, the germination start time of P. utilis seeds was delayed and the duration was longer. The germination rate, germination potential and germination index were gradually decreased, and the difference was significant with the control (P<0.05); under 15% PEG stress, the germination rate, germination potential and germination index of P. utilis increased compared with 10% PEG stress; when the PEG stress reached 20% or above, seeds could not germinate. (2) The content of proline and malondialdehyde in the leaves of P. utilis increased as PEG concentration and prolonged stress time increased. The increase of proline in the 6^th day of stress was higher than that of malondialdehyde. On the 9^th day, the proline increase was smaller than the malondialdehyde increase. (3) With the prolongation of PEG stress time, the activities of catalase and superoxide dismutase in the seedlings of P. utilis increased firstly and then decreased and the highest activity was found in all treatments on the 6^th day. While the activities of peroxidase firstly decreased and then increased, and the lowest activity was found on the 6^th day.

ConclusionThe seeds of P. utilis could germinate normally under mild drought stress, and the seedlings could actively adapt to the drought stress by regulating the content of osmotic adjustment substances and antioxidant enzymes in the body, which showed good adaptability to the arid environment.