| Daqing grassland drought habitat of Heilongjiang and landscape application lack perennial ornamental plant resources.The study took ornamental Syneilesis aconitifolia of the Daqing natural grassland vegetation as test materials, by studying the effect of the different temperature, illumination, seed harvest time and PEG simulated drought stress on seed germination to build the optimal process with seed breeding technology; By observing the characteristics of growth and development rhythm of Syneilesis aconitifolia in Harbin open field cultivation to determine the feasibility of the applications on the local and the availability as germplasm resource; By studying the correlation of indoor PEG simulated drought stress and outdoor artificial water drought stress of Syneilesis aconitifolia with physiological indicators and photosynthetic characteristics, combining with the water treatment to analyze the effect of different intensity of drought stress on the growth, morphological characteristics and physiological processes evaluating the drought adaptability of Syneilesis aconitifolia, synthetically, in order to provide a scientific basis for the seedling production and application of different drought habitat.(1) Basic properties of Syneilesis aconitifolia seeds expressed as:Syneilesis aconitifolia seed is the big-sized seed, the1000-seed weight of the mature seeds is3.974g, the relative water content was13.38%. Seed germination is insensitive to light, while temperature and seed maturity are important factors determining seed germination. the optimum temperature for seed germination of20℃, the germination rate is95%. PEG stress has a significant effect on seed germination,5%～10%PEG stress can promote seed germination,dwarfing seedlings,while15%～25%PEG stress inhibit seed germination, seeds rewatered after25%PEG stress can increase seed germination rate, and keep the seedlings tidy. On the production practice, using the seed of harvested in late September, combining20℃with5%～10%PEG stress of seed breeding process to improve seed germination rate and seedlings uniformity.(2) In2012, the characteristics of growth and development rhythm of Syneilesis aconitifolia in Harbin expressed as:The seedling stage was5℃above of the lowest temperature at the end of April, in early October the average minimum temperature was6℃into withering period. The leaf period lasted140days, Florescence was from June to July, fruit period was from August to September. The best viewing period of Syneilesis aconitifolia was from May to July, the optimal harvest time for the seeds in late September.(3) PEG simulated drought stress affected the morphological structure and physiological characteristics of Syneilesis aconitifolia seedlings. Under10%,20%and30%PEG stress, Syneilesis aconitifolia started gradually lost ornamental in32h,24h and16h, respectively; As the PEG concentration increased and stress time prolonged, leaf relative water content decreased, which has significant negative correlation with the PEG concentration and stress time; The relative conductivity, MDA content and SOD activity, with PEG concentration and stress time had significant positive correlation; Soluble protein content had no significant correlation with PEG concentration and stress time. Related physiological indexes could not recover to normal after rewatered.(4) Artificial water control drought stress had significant effects on physiological indexes and photosynthetic characteristics of Syneilesis aconitifolia seedling. Stressed for20days, ornamental decreased,25days drought causes the part of Syneilesis aconitifolia on the ground to dead, it can send out new leaves again after rewater; Soil moisture, chlorophyll b content, net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) were negatively correlated with the stress time; The relative conductivity, malondialdehyde (MDA) content, POD activity was positively correlated with the stress time, those could be used as effective factors of drought adaptability; Leaf relative water content, chlorophyll a content, SOD activity, soluble protein content, the intercellular CO2concentration (Ci), water use efficiency (WUE) had no significant correlation with stress time, could be used as reference. |
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