Seed Germination And Physiological Characteristics Of Scilla Scilloides On Drought Stress

For the cold and arid habitats of Heilongjiang and the lack of suitable germplasm resources in landscape, the exploitation and utilization of low-cost local resources have great importance to the sustainability of the built of local plant communities and species diversity. Scilla scilloides, a kind of wild perennial flower naturally distributing in Northeast, with a high ornamental value, had not be used in landscaping yet. An experiment was conducted to study the effects of the different light, temperature, water stress induced by polyethyleneglycol (PEG) and the impact of different media on seeds germination of Scilla scilloides, observed germination rate, germination index, vigor index and seedlings physiological indicator respectively, in order to build the technical process of high-quality seedling cultivation from Scilla scilloides seeds.At the same time, another experiment was conducted to study the adaptation of Scilla scilloides to drought stress by indoor simulative stress with water stress induced by PEG on scilla Scilloides seedlings and seedlings, and drought stress in pots on Scilla scilloides seedlings, observed photosynthetic characteristics and physiological characteristics of Scilla scilloides seedling on different drought stress and rewatered, in order to provide a theoretical basis and technical support for Scilla scilloides applied to the lanscape.1. Biological characteristics of Scilla scilloides seeds expressed as:Scilla scilloides seed is the small-sized seed,it has reached a mature state, with the structure of the complete embryo, with the basic physiological and structural characteristics of seed germination, the1000-seed weight of the mature seeds was2.9658g,the relative water content was19.17%. Scilla scilloides seeds is insensitive to light, while temperature is an important factor determining seed germination. Variable temperature ranging from20to30degrees C is most suitable for seed germination,but the consant temperature inhibits seed germination. PEG concentration of5%、10%stress can promote the Scilla scilloides seed germination, but drought stress inhibit seedling growth. Scilla scilloides seeds rewatered after PEG concentration of25%stress can increase seed germination rate, and keep the seedlings tidy and short. Variable temperature ranging from20to30degrees C and drought stress used in production can get high-quality seedlings. The matrix for cultivation most suitable for Scilla scilloides seed germination and seedling growth is the proportion1:1of coarse sand and peat soil ratio.2. The morphological changes of Scilla scilloides seedlings water stress induced by PEG and drought stress in pots are basically the same,all showed wilting speed became fast with the strengthening of stress. Rewatered after the leaves became dry and lost viability by the PEG osmotic stress,7days later, new leaves grow from the bulbs; Scilla scilloides seedlings water stress induced by drought stress in pots for30days, the ground part of the leaves fell off, rewatered for10days, new leaves grow from the bulbs. Drought stress affect of Scilla scilloides growth. Dry weight per unit area of Scilla scilloides leaves became the highest when stress for12days, was102.04%of the control group, began to decline after stress for30days, the leaves fell off, the ornamental lost.3. The impact of photosynthesis for Scilla scilloides is significant under drought stress time in dots, net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) had positive correlation with stress strength, the intercellular CO2concentration (Ci) had negative correlation with stress strength. After rewatered, the indicators restored, the higher the stress became, the slower the indicators restored. Scilla scilloides suffered the irreversible damage when was stressed by30days.4. The leaf physiological changes of Scilla scilloides seedlings water stress induced by PEG and drought stress in pots are basically the same. Leaf water content, conductivity, MDA content, activity of SOD, soluble protein content all can be used as the Scilla scilloides drought resistance evaluation, leaf water content had negative correlation with stress strength, conductivity and MDA content had positive correlation with stress strength; with stressthening of stress strength, the activity of SOD increased first and then decreased, the soluble protein content decreased, first and then increased.After rewatered, the relevant physiological indicators restored, the relevant physiological indicators no longer restored by the irreversible damage.5. The bulb physiological changes of Scilla scilloides seedlings water stress induced by PEG and drought stress in pots are basically the same with the leaf physiological changes. Scilla scilloides has not reached the fatal injury parameters in the entire process, the indicators have been recovered after rewatered. Scilla scilloides bulbs have high drought adjust capacity, they could regenerate after rewatered even if the leaves fall off.