The Physiological Response Of Lily To Alkaline-Salt Stress

Lily is one of important ornamental flowers. But cut flower lilies, bred in the Netherlands and Europe and America, are very strict with their growing environment, preferring cool, moist and relatively acid environment. Most of them are sensitive to alkaline-salt, especially the oriental hybrid lily which is one of the main cultivated varieties in the market. Soil salinization is very serious in western China, eastern coastal area and north of the Yangtze river, especially in the north and western region of China, which is not suitable for cut lily flower lilies growing. This lead to quality and yield of cut flower lilies and potted-lilies decrease, and limit the application of lily in landscape.Therefore, the study of lily physiological adaption mechanism under salinity-alkalinity stress, the establishment of the adaptability evaluation index are significant for breeding salt-tolerant lily genotypes.In this experiment,four mechanisms(osmotic regulation、antioxidant substances regulation、ion absorption and distribution regulation、organic acid regulation) under different concentrations of NaHCO? stress were compared between L. regale Wilson(salt tolerance) and ‘Sorbonne’(salt sensitiveness), to illustrate the adaptive mechanisms and evaluation index of Lily under alkaline-salt stress. The main results are as follows:Under NaHCO? stress, the chlorophyll and carotenoid content decrease and the MDA content and relative electrical conductivity increase. The damage degree of L. regale is lower than ‘Sorbonne’.(1)Soluble protein, proline content increased with the concentration of alkaline-salt increasing. Soluble sugar content increased under lower concentration of NaHCO? stress, then decreased under higher concentration. But L. regale can increase more soluble protein and maintain established soluble sugar content than ‘Sorbonne’.(2)ASA content increased under lower concentration of NaHCO? stress, then decreased under higher concentration. And the activities of SOD and GR had the same trend, but SOD and GR activity of L. regale is higher than ‘Sorbonne’. The activity of APX and GSH content decreased sharply under higher concentration of alkaline-salt.(3)Na+ mainly accumulated in middle leaves and upper leaves in ‘Sorbonne’, but stem and middle leaves in L. regale Wilson. Middle leaves and upper leaves seemed to be main storage organs for Na+ in ‘Sorbonne’, but stem and middle leaves in L. regale Wilson. Compared with ‘Sorbonne’, L. regale Wilson had a higher K+ /Na+ ratios in root, middle leaves and upper leaves. This is one of reasons for the stronger salt tolerance of L. regale.(4)The content of oxalic acid, lactic acid and acetic acid in L. regale Wilson increased, but the relative content is less. The malic acid and acetic acid in ‘Sorbonne’ increased. This showed acid regulation is not the reason for the stronger salt tolerance of L. regale.All the data indicated that compared with ‘Sorbonne’, L. regale Wilson could maintain a higher K+ /Na+ ratio through absorbing a small amount of Na+ and constraining Na+ in the root, and increase SOD activity、ASA content under low concentration of alkaline-salt, increase soluble protein content and maintain established soluble sugar content under higher concentration of alkaline-salt, all of which are good explanations for its alkaline-salt tolerance.