Studies On Physiological And Biochemical Haracteristics Related To NaCl Stress In Strawberry (Fragaria Ananassa Duch.)

Strawberry, a perennial herbage plant, is sensitive to salt. The aggravation of soil saltinization limits its proper growing range. For widening its distribution range and studying its salt tolerance, this experiment studied the characteristic of physiology and biochemistry in strawberry under NaCl stress by potted plant and tissue culture. Three conventional varieties, Darselect, Toyonoka and All Star, from both field and subculture plant in vitro were used. The results are summarized as below:1. The growth was restrained under NaCl stress. With NaCI content increasing and stress time prolonging the injury degree and index of salt damage of strawberry leaves increased, moreover the leaf area and the accumulation of biomass decreased rapidly. The leaf area was sensitive to NaCl stress. The top of the plant is more sensitive to NaCI than roots. So the ratio of root/stem went up with the NaCl stress intensify increasing. The growth index of different varieties had differences.2. Studies on physiological and biochemical characteristics of strawberry to NaCl stress. Under NaCl stress, the SOD and POD activity in leaves decreased after increasing with NaCI content increasing and stress time prolonging, and the salt tolerance was the best while the activity maintains high level in a long time. The content of MDA and cell membrane permeability in leaves went up with stress intensify enhancing, and the bigger increased extent was, the smaller the salt tolerance was. The content of free proline, soluble protein and soluble sugar in leaves increased under low and short-term NaCl stress, but decreased under high and long-term NaCl stress. The peak period was different among treatments, the later peak arisen, the more the salt tolerance was. To some extent the more increasing of soluble sugar, the more salt tolerance is.The content of Na+, CI" and the ratio of NaV K+ in the leaves of strawberry were increased with salinity addition. The content of K+ had no change in potted plant, meanwhile, increased in subculture plant with salinity addition. The content of chlorophyll and relative water decreased with NaCI content increasing and stress time prolonging, the lower the ratio to control was, the smaller salt tolerance was. Under NaCl stress the change trend of physiological and biochemical indexes concerned with salt tolerance in subculture plant was the same as that of potted plant. Therefore, thesubculture plants could be used to study salt tolerance of strawberry.3. According to synthesis comparison to the growth and physiological and biochemical reaction of three varieties under NaCl stress, it was found that the sequence of salt tolerance is Darselect > Toyonoka > All Star. The salt tolerance of Toyonoka was more than All Star in the condition of tissue culture.4. According to analysis of indexes concerned with salt tolerance, the activity of SOD and POD, the content of MDA, cell membrane permeability, soluble sugar, Na+, Cl~ and the ratio of NaV K+ in strawberry leaves can be used as evaluation indexes of salt tolerance of strawberry varieties. The content of free proline, soluble protein, chlorophyll and relative water can be used as reference indexes.