Influence Of Environmental Factors On Seed Germination Of Salix Linearistipularis

Salix linearistipularis is a small tree that belongs to salix of salicaceae.Due to its good resistance to drought, barren soil and saline alkali, it is a rare woody plant that is naturally distributed in Songnen Plain. Although S. linearistipularis has high seed rate and produces a large number of seeds every year, mostly of them exist as single plant in Songnen Plain, its population size is very small, and has not yet formed into large natural distribution, seeds that naturally fall from S. linearistipularis have very low survival ratio, the reason still needs to be investigated. In this paper, S. linearistipularis seeds and young seedlings as experimental material, to research the physiological characteristics of S. Linearistipularis seeds and the effect of environmental factors on the seed germination and the seedlings growth, seed germination characteristics understand Mongolia Liu. Investigating the environmental factors that affect the natural regeneration of S. linearistipularis, so as to reveal the main reason for the large yield of S. linearistipularis seeds but very few seedlings, and provide theoretical basis and experimental data for the further development and utilization of S. linearistipularis resources in saline-alkali land and improvement of saline-alkali soil.Our results were shown below:(1) Seed physiological characteristics:The mature S. linearistipularis seeds were long cylindrical type, composed by the seed coat and embryo. The cotyledons contain carbohydrates, lipids, proteins and other substances, and the content is high; The seeds were very small and had pappus; The seeds of high quality, but low water content; Seeds have very high water absorption rate, the water absorption capacity of seed reaches the maximum 200.50% at the 30th minute; The seeds have no dormancy, the germination speed is very fast and the germination rate is high.(2) Effects of environmental factors on the seed germination:The most suitable medium for germination is medium with 0.8% agar alone; The suitable temperature for seed germination is 25-30℃; Light neutral seed; Seed has strict requirements on soil moisture, and only begins germination when it has sufficient water content, the optimum soil moisture is 100-200%, and it will not germinate when the water content is less than 25%; Low concentration of PEG (6000) stress could promote the germination of seeds, the high concentration of PEG (6000) stress severely inhibited the seed germination; The seed is short-lived seed, the germination rate of seeds in 45 days at room temperature is 3%; after being stored at -80℃ for one year, seed germination rate is still 50%.(3) The effect of saline-alkali stress on the seed germination and seedlings growth:With the increase of NaCl concentration, seed germination rate, germination potential, germination index, vigor index and other indicators are gradually reduced; With the increase of NaHCO3 concentration, the germination rate, germination potential and germination index, and other indicators are gradually reduced, but vigor index, root length, seeding length and other indicators first increased and then decreased, and reached the maximum in 10mmol/1 NaHC03.(4) The effect of saline-alkali stress on the anatomical structure of leaf and root:Seedings growth about one months show strong endurance under the stress of 50mmon/L NaCl and 10mmon/L NaHCO3 solutions, and the seeding growth is best in 10mmon/L NaHCO3. Under the stress of such solutions of high concentration, certain degrees of endurance also present in the roots and lamina, with the anatomical results like the thicken of root endodermis, the enlargement of vascular bundle in diameter, the vanish of aerenchyma tissures and, the closure of lamina stoma.Overall, the seeds of S. linearistipularis have a certain ability to resist saline-alkali. In Songnen Plain, the number of S. linearistipularis seeds are very much, but seedings are a little, the main reason is the dislocation of seed longevity and the local rainy season. So the seeds should be collected together in the end of May, and stored at-80℃. And using of artificial way to get a lot of healthy planting seedling nursery.