【作者】 张华；

【导师】 刘大林；

【作者基本信息】 扬州大学 ， 草业科学， 2014， 硕士

【摘要】 狼尾草属(Pennisetum Rich)牧草是一年生或多年生禾本科牧草,在热带、亚热带和温带地区广泛种植,具有产量高、营养价值高以及用途范围广等特点。有研究表明：狼尾草具有一定的耐盐性,且土壤中添加适量硅可以显著提高植物的抗盐性,降低植物盐害,但是硅对于缓解盐胁迫下狼尾草属牧草的生长及生理生化指标的相关研究报道较少。本文主要研究了外源硅对盐(NaCl)胁迫下两种狼尾草的生长和生理生化特性的影响。研究包括三个部分,结果如下：1.硅对NaCl胁迫下两种狼尾草的生长指标的影响研究在不同浓度的NaCl处理组(1.0、2.0、4.0g·kg-1)土壤中添加不同浓度硅(0.26、0.52、0.78、1.04g·kg-1)对两种狼尾草的株高、分蘖数以及其他生长指标的影响。结果表明：低浓度NaCl处理组(1.0g·kg-1)狼尾草的株高、分蘖数以及其他生长指标高于对照组(未加NaCl处理)；较高浓度NaCl处理组(2.0、4.0g·kg-1)的株高、分蘖数以及其他生长指标显著低于对照组(P<0.05)。不同浓度硅处理对NaCl胁迫下两种狼尾草的株高、分蘖数以及其他生长指标有促进作用,其中硅的浓度为0.78、1.04g·kg-1对狼尾草的促进效果最佳。2.硅对NaCl胁迫下两种狼尾草的生理生化指标的影响研究在不同浓度的NaCl处理组(1.0、2.0、4.0g·kg-1)土壤中添加不同浓度硅(0.26、0.52、0.78、1.04g·kg-1)对两种狼尾草的叶绿素含量、细胞膜透性和脯氨酸含量等指标的影响。结果表明：NaCl胁迫会影响两种狼尾草的生理生化指标,高浓度硅(1.04g·kg-1)提高了两种狼尾草的叶绿素含量,0.78、1.04g·kg-1浓度的硅显著降低了美洲狼尾草和杂交狼尾草的相对电导率和叶片的脯氨酸含量(P<0.05),说明加硅后可以降低NaCl胁迫下两种狼尾草的生理生化指标,且0.78、1.04g-kg-1浓度的硅对两种狼尾草的缓解效果最佳。研究在不同浓度的NaCl处理组(1.0、2.0、4.0g·kg-1)土壤中添加不同浓度硅(0.26、0.52、0.78、1.04g·kg-1)条件下对两种狼尾草的丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性以及过氧化物酶(POD)活性等指标的影响。结果表明：硅降低了两种狼尾草的MDA含量,降低SOD和POD活性,且随硅浓度的增加MDA含量降低显著(P<0.05), SOD、POD活性降低显著(P<0.05),1.04g·kg-1浓度的硅效果最显著。通过对两种狼尾草的生理生化指标研究结果表明：硅通过调节狼尾草的自身抗逆性、抗氧化酶系统以及酶促保护系统来达到缓解NaCl胁迫的作用。3.硅对NaCl胁迫下两种狼尾草营养品质的影响研究在不同浓度NaCl的处理组(1.0、2.0、4.0g·kg-1)土壤中添加不同浓度硅(0.26、0.52、0.78、1.04g-kg-1)条件下对两种狼尾草的粗蛋白、粗灰分、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)等指标的影响。结果表明：NaCl胁迫可以降低两种狼尾草的粗蛋白含量,对其他营养指标影响不大,加硅对狼尾草的营养品质影响不大,不会对其营养成分产生影响。由此可见,在NaCl胁迫下加外源硅可以通过调节狼尾草体内的渗透调节物质、抗氧化酶系统以及促进生长指标等途径来发挥协同作用,在不影响狼尾草本身的营养品质前提下提高狼尾草的抗盐能力。更多还原

【Abstract】 Pennisetum Rich is an important forage grass in tropical, subtropical and temperate regions with annual or perennial species. There are many advantages for Pennisetum Rich, such as high yield, long period of supplementation, high crude protein content and wide range of use. Some studies shown that pennisetum have some salt tolerance, and the salt resistance can be significantly improved by adding appropriate amount of silicon in the soil. However, the mechanism of silicon alleviating salt stress in pennisetum is still unclear. We conducted our research to explore the mechanism of Si alleviate NaCl stress in two kinds of pennisetum. The study included three parts:1. The influence of biological characteristics which Si alleviate NaCl stress to pennisetumDifferent concentration of Si (0.26,0.52,0.78,1.04g·kg-1) were added to the soil with different concentration of NaCl (1.0,2.0,4.0g·kg-1). Two kinds of pennisetum were used to do the experiment. Height, number of tillers and other biomass indicators were measured. The results showed that height, tiller number and biomass under low NaCl treatment group (1.0g·kg-1) was higher than the control group, while high NaCl treatment group (2.0,4.0g·kg-1) significantly (P<0.05) lower than the control group. Different concentration of Si all promoted height, tiller number and biomass of two kinds of pennisetum under NaCl stress. It stated that low concentration of NaCl stress can promote the growth of pennisetum, but high concentration of NaCl stress can significantly (P<0.05) inhibit its growth, Si can alleviate NaCl stress on the growth of pennisetum, Si (0.78,1.04g·kg-1) had the best promotion effect on pennisetum.2. The influence of physiological and biochemical indicators which Si alleviate NaCl stress to pennisetumDifferent concentrations of Si (0.26,0.52,0.78,1.04g·kg-1) were added to the soil with different concentration of NaCl (1.0,2.0,4.0g·kg-1). Two kinds of pennisetum were used to do the experiment. Chlorophyll content, the leaf cell membrane permeability and proline content were measured. The results showed that NaCl stress affected the physiological and biochemical characteristics of two kinds of pennisetum. The high concentration of Si (1.04g·kg-1) processing can improve the chlorophyll content,0.78g·kg-1and1.04g·kg-1Si processing reduced the relative conductivity and proline content of leaves. It illustrated Si can alleviate physiological and biochemical characteristics of two kings of pennisetum under NaCl stress. Si0.78,1.04g·kg-1had the best ameliorating effects on pennisetum.Different concentrations of Si (0.26,0.52,0.78,1.04g·kg-1) were added to the soil with different concentration of NaCl (1.0,2.0,4.0g·kg-1). Two kinds of pennisetum were used to do the experiment. MDA content, SOD and POD activity were measured. Results showed that Si can reduce MDA content, SOD and POD activity of two kinds of pennisetum. With the increase of Si concentration, MDA content, SOD and POD activity declined more and more obviously,1.04g·kg-1Si had the most significant effect (P<0.05).The results showed that Si can adjust pennisetum own resistance mechanisms, antioxidant enzyme systems and enzymatic protection systems to achieve remission role of NaCl stress.3. The influence of grass nutritional quality which Si alleviate NaCl stress to pennisetumDifferent concentrations of Si (0.26,0.52,0.78,1.04g·kg-1) were added to the soil with different concentration of NaCl (1.0,2.0,4.0g·kg-1). Two kinds of pennisetum were used to do the experiment. CP content, Ash content, NDF content and ADF content were measured. The results show that NaCl stress can reduce the crude protein content of two kinds of pennisetum, but have little effects on the other nutrition indicators. Si has little effect on nutritional parameters under NaCl stress in pennisetum and Si will not affect nutritional ingredients of pennisetum.Results show that applying Si to pennisetum can response NaCl stress through the osmotic adjustment, antioxidant enzyme systems and other ways to promote biological yield, and it improves the NaCl resistance of without affect nutritional quality of pennisetum itself.更多还原