滴灌模式下生物菌肥的制备及其对棉花解盐促生机制研究

The phenomenon of soil salinization in Xinjiang, due to the long-term drip irrigation system under the mulch model used for plant cultivation, has become more serious. So some bacteria with alleviation of salt stress and growth promotion obtained previously by our research group will be as objects of study and the main goals of this work will to obtain the bacterial fertilizers and to clarify its mechanism for alleviating salt stress and promoting growth on cotton application under drip irrigation model. The high density culture process and the key technical parameters of these bacteria and which how related to bacteria cell growth and performance would be investigated. Through screening appropriate nutrient carrier systems and auxiliary systems of the bacterial fertilizer, the bacterial fertilizer products suitable for the application of drip irrigation mode and the key preparation techniques for realizing the stability of the bacterial content, easy to colonization and ensuring the effect of the products will obtained. Using the pot and field experiments, we will study that mechanism of alleviating salt stress and growth promoting of the bacterial fertilizer on cotton and the interaction effect of bacteria and cotton under the different salt stress conditions. In addition, the critical applications parameters of bacterial fertilizer under drip mode, such as application amount, frequency and cycle and the relationship between these applications parameters and effect of the cotton for alleviating salt stress and promoting growth will been explained, which to meet the needs of crop growth under drip irrigation patterns. Further to reveal the laws of colonization, survival cycle, hold effecting and population fluctuation of the bacteria in the rhizo- and endosphere of plants. Thus, this is to establish theoretical foundation and provide technical support for broadening the application areas and effectiveness of the biological bacterial fertilizer and solving the problem of soil salinization due to the long-term drip irrigation.

针对新疆长期滴灌模式产生的土壤盐渍化问题日益严重的现象，以课题组前期筛选获得的具有缓解盐胁迫促进作物生长的解盐促生菌为研究对象，以获得膜下滴灌模式应用的生物菌肥及阐明菌肥对棉花解盐促生机制为目标，研究解盐促生菌的高密度培养最佳工艺及关键技术参数对菌体的生长及性能的相关性；通过筛选合适的解盐促生菌的营养载体系统和助剂系统，获得适合滴灌模式应用的菌肥产品及实现产品中菌体含量稳定、易于定殖，效果保证的关键制备技术。通过盆栽及田间试验，研究不同盐胁迫条件下解盐促生菌肥对棉花的解盐促生作用机制及与棉花的互作效应；阐明菌肥滴灌模式的施入量、施入次数及周期等关键应用参数及对棉花解盐促生作用效果的关系，以满足滴灌模式作物生长的需要。进一步揭示解盐促生菌株在棉花根际的定殖、存活周期、持效时间及数量消长等规律。从而为拓宽生物菌肥的应用领域与功效，以及解决长期滴灌产生的土壤盐渍化问题奠定理论基础和提供技术支持。

针对新疆因长期滴灌产生的土壤盐渍化日益严重的现象，项目以前期自主筛选的解盐促生菌为研究对象，开发出了适合膜下滴灌模式应用的具有解盐促生功能的生物菌肥，产品性能稳定、易于定殖。研究了菌株的高密度培养工艺，考察了不同盐胁迫条件下菌肥对棉花的解盐促生作用机制及与棉花的互作效应，进一步探讨了菌株在棉花根际的定殖、存活、持效时间及数量消长等规律。主要研究结论如下：.1、确定了菌株Rs-198的廉价培养基组分为玉米粉52.26 g/L，豆粕15.66 g/L，K2HPO4 2.34 g/L，MnSO4 0.18 g/L，NaCl 5 g/L，确定了菌株最佳培养时间为36 h，接种量3%，生长温度30℃，转速170 rpm，装液量为在250 mL三角瓶中装盛100 mL。在此条件下，菌株Rs-198溶磷量、IAA产量及菌体密度分别为69.56 mg/L、21.13 mg/L、3.2×1013 cfu/mL。.2、确定了4种Rs-198液体菌肥剂型配方，在第180天，菌肥中的有效活菌数均大于107 cfu/mL。不同盐胁迫条件下，液体菌肥处理能够提高棉花种子的发芽率，植株的株高、根长、鲜重及干重；降低棉苗植株中MDA和脯氨酸的含量，和棉苗中SOD、POD、CAT、PPO的活性。.3、确定了海藻酸钠浓度为2%，菌胶比为1:3，碳酸钙浓度为2.5%的条件下，利用内源乳化法制备获得了SL-13微胶囊。在壁材中加入明胶，微胶囊的粒径分布在微米级范围且形状近似圆形、分散性较好，且通过改变明胶的含量能够有效地调控微胶囊的粒径分布及释放特性，可以满足农作物生长周期的需要。.4、海藻酸钠-膨润土-淀粉复合壁材微胶囊能够显著提高SRPG-396菌株的储存稳定性，且不会影响其产IAA和GA的能力。揭示了解盐促生菌株在棉花根际的定殖、存活及消长规律，即在棉苗的生长初期，接种微胶囊处理的棉苗根基、根中和根尖的定殖数量都少于游离菌处理下的定殖数量，但是在28天后接种微胶囊处理的棉苗根部蛭石、根基、根中和根尖的定殖数量开始超过游离菌处理的定殖数量，且在根中的定殖的活菌数量要比根尖、根基和蛭石中的活菌数量多。.该项目的研究结果已发表SCI论文9篇，中文科技核心文章1篇；申请中国发明专利6项，均已进入实质审查阶段；参加国内外学术会议2次；培养硕士研究生3名，指导1篇研究生论文获石河子大学优秀硕士学位论文奖。