| Oenothera parviflora is the biennial plant of Oenothera. One of the invasive spieces invasive weed native to the eastern America. The survey found that O. parviflora have been distributed Liaoning, Jilin, Heilongjiang and Hebei Province, parts of the Northeast of China. It has been formed the dominant species of the population and have strong invasiveness. In this study, by using culture dish and potwater controlling method, study the response of seeding germination and photosynthetic indexes under different moisture,temperature and light. The research on the adaptability of O. parviflora under different drought stress conditions will offer a scientific base for the introduction and extension of this species. The main results were as flow:1. Temperature and light on O. parviflora seed germination and growth of seedlings.The results show that under low temperature is limiting its germination conditions and light appropriate to promote seed germination. O. parviflora could germinate at 20-30℃,where the optimum germination conditions 25℃ light 24h/d; low temperatur inhibition O.parviflora seedling growth, temperature 30℃ O. parviflora primary root growth and increase the biomass, and optimum growth temperature of 30℃ light 0h/d. It suggest that O. parviflora as invasive plants have the time and the geographical pattern of diffusion.2. A certain concentration of PEG-6000 simulated drought stress on Oenothera parviflora seed germination and seedling growth has different influence. The results show that the PEG concentration is 20% seedlinggrowth was inhibited(P<0.05)when the PEG concentration of 25% of the seeds did not germinate. low concentrations of PEG on germ,primary root growth and biomass increase significantly inhibited, 20% PEG treatment O.parviflora seedling stopped growing; after the lifting of 25% PEG stress,(P<0.05)O.parviflora seeds germinate quickly tidy. It suggest that O. parviflora has a certain adaptability to drought stress.3. Under mild drought treatment solution protein increase significantly(P<0.05),other physiological index did not change significantly( P < 0.05), moderate droughtchlorophy content decrease significantly(P<0.05),MDA、solution protein、SOD、POD significantly increase(P<0.05), serve drought the chlorophy content was significantly decrease(P<0.05), SOD、POD significantly increase(P<0.05),cause soluble protein significantly increase(P<0.05), MDA decrease. It suggest that O. parviflora protective enzyme system can regulate physiological indices under drought stress, has a strong ability to adapt drought stress.4. By successive of water loss, at different levels of soil drought, the change of photosynthesis and fluorescence parameters of O. parviflora. The results showed that mild and moderate drought stress Pn reduce mainly due to stomatal factors, Which under moderate drought Tr、Cond、Ci significantly decrease(P<0.05); serve and extreme drought the Pn reduce mainly reason for non-stomatal factors, at the same time Tr、Cond significantly decrease(P<0.05), Ci、WUE significantly higher(P<0.05). O. parviflora by closing pores、reduce transipiration rate、improve water use efficieny to adapt to the growth under drought conditions, O. parviflora show has some drought tolerance.5. By successive of water loss, at different levels of soil drought, the change of photosynthesis and fluorescence parameters of O. parviflora. The results showed that O.parviflora under mild drought stress Fv/Fm, Yield, ETR, qP decreased, the difference was not significant(P>0.05); moderate drought stress Fv/Fm, Yield, ETR, qP decreased significantly(P<0.05); severe drought, extreme drought stress under qN increased signific antly(P<0.05), Fv/Fm decreased to 0.5. It suggest that when O. parviflora reaches severe drought stress PSII reaction centers of light damage, resulting in photosynthesis is affected,by increasing heat dissipation consumption absorb light energy avoid the light damage chloroplasts. |
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