Study On Cultivation Techniques Of Elaeagnus Angustifolia L. In Saline Soil And Selection Of Salt-tolerant And High-quality Plants

Soil salinization is one of the major causes of declining agricultural productivity in many arid and semiarid regions of the world.The Yellow River Delta is known as the“Golden Triangle”zone and is one of the three major estuarine delta of the country.And it is an important economic development zone in China.The land in the Yellow River Delta has low utilization rate because of its bad physical and chemical properties and high salt content,which limited the urban road greening of around the Yellow River Delta.As a result,fewer types of garden plants are planted on the saline soil in the Yellow River Delta,and the landscape ecosystem is relatively simple.Elaeagnus angustifolia L.has important ecological value and plays an important role in sand fixation,soil and water conservation,vegetation restoration and afforestation.It can be used as urban greening tree species in the Yellow River Delta.In this experiment,the selection and application of salt-tolerant and high quality E.angustifolia in the saline land in the Yellow River Delta were studied,which provided a theoretical basis for introducing it to the local area as a tree species for afforestation.And,with the gamma radiation good characters of the E.angustifolia mutant will be obtained.The experimental results are as follows:1.Selection of salt-tolerant and high quality E.angustifolia:The main disadvantage of the tree species is that the trunk is not erect,the shrub traits is too strong,the tree is not beautiful,and it is not good for ornamental plants.In this experiment,E.angustifolia seedlings were selected through a two-year planting experiment from the collected seeds in Shiyanghe of Gansu Province,Jinchang of Gansu Province,Xinjiang,Turpan of Xinjiang Autonomous Region and Linhe of Inner Mongolia.The horticultural traits,leaf color,leaf shape,and biomass were analyzed and compared.A comparative analysis of the conditions yielded 18 strains of E.angustifolia with good traits.We have selected excellent individuals with a beautiful tree shape and distinctly superior apical dominance.These individual plants can multiply by vegetative propagation.The urgency of the lack of green tree species in the area has been alleviated.2.Effects of ⁶⁰Co gamma ray irradiation on E.angustifolia germination and seedling growth:In this experiment,different doses of ⁶⁰Co gamma ray radiation?0Gy,400 Gy,600 Gy,800 Gy and 1000 Gy?were used on the E.angustifolia,Jinchang,China.The LD₅₀ for ⁶⁰Co gamma ray irradiation was based on the survival rate of seedlings.According to the experimental results,we found that the germination rate?GR?,germination potential,and germination index?GI?of the seeds were not significantly different between the radiation-induced group and the control group,but the root length was significantly shortened by gamma ray irradiation.The seed vigor is significantly reduced.We measured the survival rate of E.angustifolia seedlings after radiation treatment.The results showed that with the increase of radiation dose,the survival rate of E.angustifolia seedlings was significantly reduced.Based on linear regression of the logarithm of emerged seedling vs.gamma radiation dose,the LD₅₀ for ⁶⁰Co gamma ray irradiation was 538.5 Gy.Under the 1%Na Cl treatment conditions,the germination rate,germination potential,germination index,root length and seed vigor were reduced.The germination potential and germination index of E.angustifolia seeds were not significantly different among the radiation groups,but the root length and the seed vigor were significantly reduced,which was consistent with the non-salt conditions.The resulting based on linear regression of the logarithm of emerged seedling vs.gamma radiation dose,the LD₅₀ for ⁶⁰Co gamma ray irradiation was 347 Gy.3.The cultivation techniques for E.angustifolia in saline land as followings:This experiment explored a set of cultivation techniques suitable for planting E.angustifolia in the Yellow River Delta area:that is,irrigating of the Yellow River water in early April.Before planting E.angustifolia,application of 300 kg/hm² of DAP?13%nitrogen and 44%of phosphorus?compound fertilizer.According to the soil moisture and the hardness of seeds from different provenances,the seeds were immersion in water for 2-7 days before sowing.The seeds were sowed timely and the row spacing is controlled at 60-80 cm,and the plant spacing was controlled at about20 cm.After sowing,cover the loose soil 0.5-1.0 cm,cover the mulching film timely and according to the growth of seedlings,timely release seedlings and seal the membrane.Urea 300 kg/hm² topdressed at a height of 30 cm.Pruning branches regularly:Pruning branches at heights of 50 cm and 1 m,and trimming the extra tills every other month until October.In the second year of May-June,the extra pruning will continue to be pruned,and it will be trimmed again from September to October.The E.angustifolia tree will has obvious apical dominance,erect trunk,and strong ornamental quality.Generally 2-3 years,the E.angustifolia can become lumber.4.Adaptive growth response of exotic E.angustifolia to indigenous saline soil and its beneficial effects on the soil system in the Yellow River Delta:E.angustifolia seedlings were introduced to the Yellow River Delta in 2014 and 2015,respectively,determines the growth of E.angustifolia and its impact on the land.The results showed that on the saline soil with 0.4-0.8%salinity in the Yellow River Delta,the seedlings of E.angustifolia grew well with high relative growth rate,bigger crown,thicker basal diameter,thicker diameter at the breast height and more branches especially during the second year.The high biomass was mainly due to the high photosynthesi.The Pn of E.angustifolia seedlings was mainly affected by Gs,chlorophyll content,air temperature.Planting E.angustifolia on the Yellow River Delta could significantly decreased the salt content of the soil,increased the numbers of fungus,bacteria,salt-tolerant bacteria,actinomycetes and salt-tolerant actinomycetes,especially for planting E.angustifolia for two consecutive years.By measuring the soil microbial content,it was found that the number of microorganisms in the soil grown with E.angustifolia increased significantly,especially salt-tolerant bacteria,actinomycetes,and salt-tolerant actinomycetes.