土壤盐胁迫下宁夏枸杞的生理反应

以宁夏枸杞(LyciumbarbarumL.)主要栽培品种宁杞一号为试验材料,研究了不同浓度土壤盐胁迫下宁夏枸杞渗透调节、光合作用、抗氧化保护系统和糖代谢等生理性状的变化,结果显示:Na鄄Cl胁迫下,宁夏枸杞渗透调节物质以无机离子为主,主要为Na 和Cl-,并随外界盐浓度的增加而增加,K 则呈现下降的趋势,叶部积累的无机离子总量高于根部,枸杞根系质膜和液泡膜H -ATPase活性逐渐增强,且液泡膜H -ATPase活性高于质膜H -ATPase活性;在等渗的PEG6000处理下,有机溶质(甜菜碱,氨基酸,可溶性糖,有机酸)含量明显增加。盐胁迫下枸杞叶片光合作用总体呈现下降的趋势,在土壤盐浓度小于6g/kgNaCl胁迫范围时,光合作用PSⅡ的光化学活性保持较强的稳定性,Pn的下降主要受气孔限制,在盐分浓度大于6g/kgNaCl时,Pn的下降的原因是非气孔限制因素引起的。外源甜菜碱对盐胁迫下枸杞叶片膜质过氧化具有较好的缓解作用。通过钌红标记定位电镜观察发现盐胁迫下枸杞叶片细胞壁表面糖蛋白层明显增厚,并且随NaCl浓度增加而增厚、致密,当浓度超过9g/kgNaCl时,其细胞璧糖蛋白层开始疏松并大量的脱落。

Physiological Responses of Lycium barbarum L. under Soil Salt Stress

Lycium barbarum L. is a famous traditional Chinese herbal medicine which has functions "nourishing the kidney and producing essence, nourishing the liver and brightening eyes." It has been widely used as health-giving food for about 2300 years. Lycium barbarum L. is a halophyte of Sloanaceae Lycium L. with a relative high salt-tolerance. Seedling of NINGQI NO.1, the main cultivated variety of Lycium barbarum L. were subjected to stress with NaCl both potted and field experiments. Several physiological characters of the plant such as Osmoregulation, Photosynthesis, Antioxidation, Betaine, and Glycoprotein were investigated. The result are showed as following: The inorganic osmotica play the most important role of leave osmotica under salt stress. With the increasing of concentration of NaCl, the content of Na and Cl- increased gradually, but the content of K declined gradually. The content of Na accumulated in leaves was higher than that in roots; the content of Cl- in roots was higher than that in leaves; K was higher than that in roots. As to the sum of ions, the inorganic ions accumulated in leaves were higher than those in roots. The organic osmotica like betaine, ammonia acid, soluble sugar and organic acid increase significant in leaves under water stress (PEG 6000). The decline of photosynthesis of Lycium barbarum L. was caused by the stomatal limiting, the growth of Lycium barbarum L. was not inhibited insignificantly, and PSII reaction center activity was remained steadily Under the NaCl concentration lower than 6g/kg NaCl; while the declining of photosynthesis of Lycium barbarum L.was caused by the non-stomatal limiting under NaCl concentration higher than 6g/kg NaCl and the growth of Lycium barbarum L. were inhibited significantly. The H -ATPase activity of the tonoplast membrane(TM) and plast membrane(PM) of the lycium Barbarum L. was increased with soil NaCl concentration. The H -ATPase activity of TM was higher than that of PM. The contribution to the active oxygen scavenging system line on Lycium Barbarum Polyaccharide (LBP), Superoxide dismutase (SOD) and Betaine. Dynamic changes of the glycoproteins, which exist at the cell surface of Lycium barbarum L. leaves, are orientated by ruthenium and observed through electron microscopy under the different salt treatments. The glycoprotein layer becomes thicker and tighter while the NaCl concentration increases under 6g/kg; but a high concentration of 6g/kg NaCl in the soil makes the layer become thinner. In which case, the layer that near the clearance of cell loosens and drops greatly. The dropped glycoprotein layer dissociates to the clearance of cells and makes the constructions become blur and some of them ruined.