Studies On Seed Allelopathy And Salt-resistance Mechanism In Seedlings Of Nitraria Tangutorum

In this experiment, Nitraria tangutorum seeds from Minqin in Gansu Province were selected as the experimental materials. The soaking solutions of the seeds following different times were used in wheat germination in order to study their allelopathy. At the same time, irrigated by water as a control, the N. tanguticum seedlings were watered by 1 % NaCl and 1% NaCl +15 mmoL.L^-1CaCl₂ solution in order to explore the mechanism of salt resistance and investigate the influence of Ca²⁺ on the salt resistance of N. tanguticum seedlings under salt stress by measuring cell membrane stability and soluble substance content in leaves, and by scanning electron microscope photographs following autopsy on the vegetative organs.The results show as follows:1. The water solution from N. tangutorum seeds have diverse effects on the wheat seed germination.The water solution soaked for 24 h inhibited the germination rate, germination index and promotes the germination vigor of the wheat variety. The water solution soaked for 36 h inhibited the germination energy, germination rate and germination index of the wheat variety.2. In the treatment of 1% NaCl salt stress with spraying 15 mmoL.L^-1CaCl₂, the electrolyte leakage and the MDA content in N. tangutorum leaf cells decreased significantly compared with the treatment of 1% NaCl salt stress, revealing that exotic Ca²⁺ can reduce MDA content, thereby protecting the integrity of membrane structure.3. In the treatment of 1% NaCl salt stress with spraying 15 mmoL.L^-1CaCl₂, the contents of soluble sugar and soluble protein in N. tangutorum leaf cells were significantly higher than that in the treatment of 1 % NaCl salt stress, which showed that Ca²⁺ can increase the contents of the soluble substances resulting in reducing physiological drought injury.4. In the treatment of 1% NaCl salt stress with spraying 15 mmoL.L^-1CaCl₂, the leaves increased stomatal frequency but reduced stomatal area, thereby reducing the area of transpiration; increased umber and density of the catheter of primary xylem to increase water supply area; improved the development of the parenchyma of roots and stems in favor of storage for nutrients and water and dilution of salt resulting in reducing salt injury.