The relationship between the accumulation of salt ions and betaine, and the photosynthesis in leaves of Lycium barbarum L. under salt stress
盐胁迫下宁夏枸杞盐分与甜菜碱累积及其与光合作用的关系

Effects of NaCl on concentrations of salt ions and glycinebetaine and photosynthesis of salt-tolerance Lycium barbarum L. are determined. The results show that leaf burn sysnptoms are very serious under NaCl stress of 9-12g/kg concentration, and slight under its concentration of 0.8-6g/kg. With the increasing of NaCl concentration and the prolongation of days of treatment, the contents of Na and Cl- are accumulated gradually. As to the NaCl concentration, the rate of photosynthesis of Lycium barbarum L. gradually decreases. When the concentration of NaCl is 0.8-6g/kg, the photosynthesis of Lycium barbarum L. leaf is decreased, which is caused mainly by the decrease of stomatal conductance. On the contrary, when the concentration of NaCl is more than 6g/kg, the photosynthesis is decreased yet. The main cause is that the photosynthetic enzyme is damaged by surplus Na and Cl accumulated in the Lycium barbarum L. leaf, therefore, the non-stomatal limitation becomes the main factor, decreasing seriously the photosynthesis and PS II photochemical efficiency. Accumulations of Na and Cl- show a trend from quick to slow, while betaine is accumulated excessively. The accumulation of betaine is also contributed to the salt resistance of Lycium barbarum L.