Studies On Stress Tolerance Of Cold-resistant Dwarf Bamboo Under Saline-alkali Stress

The problem of salinization was become to the cosmopolitan problem. How better to use the saline-alkaline soil was return to the hot problem of the study. Bamboo is the important forest resources; it has many advantages, such as the saline-alkaline resistance, fast growth, early lumber, high yield, wide application. Especially it can be wider used in the garden. So selecting bamboo as the research object of saline-alkaline resistance not only have the important theoretical significance, but also can bring huge economic benefit and social benefit.Using Pleioblastus kongosanensis f. aureostriaus and Pleioblastus argenteostriatus as the major test material, and pot culture and so on, this paper studied the dynamic changes of the growth and physiological and biochemical indexes under the saline-alkali stress, discussed and compared the character and mechanism differences of the salt-tolerance. The main research result is as follows.1.The growth state of the two bamboos under different salt stress were studied.(1) Different salt stress had different effect on the two bamboos: The growth condition was extent affected by the saline-alkaline treatments. The Pleioblastus kongosanensis f. aureostriaus all died under the C4 ( the salt concentration is 300mmol·L-1and the pH:9.96) treatment. And Pleioblastus argenteostriatus had death phenomenon under K4(the salt concentration is 300mmol·L-1 ) and C4 treatment.(2) Different salt stress treatments obvious inhibited the growth and biomass of two kind bamboo. Under the stress of the neutral salt, the tendency of the height growth showed accelerating growth firstly and then decreased. Especially when the concentration reached 300mmol.L-1, the biomass of Pleioblastus kongosanensis f. aureostriaus was only about 25% relative to the control. And Pleioblastus argenteostriatus all dead. Under the stress of the alkaline salt, the effect showed more serious for the Pleioblastus argenteostriatus. The height growth of seedlings was inhibited and the biomass was decreased under the neutral salt and alkaline salt stresses. Under different stress level, the ratio of root to stem was increased significantly; Adding nutrients distribution to root may be the main adapting stress way of two bamboos.2.Studied on the effects of salt stresses on Chlorophyll of Pleioblastus argenteostriatus and Pleioblastus kongosanensis f. aureostriaus. Under low-strength neutral salt stress, the results showed that the contend of Chlorophyll a of Pleioblastus kongosanensis f. aureostriaus leaves appeared an increasing and then declining trend and then increasing, The change of other treatments were not obvious. And the results showed that the contend of Chlorophyll a of Pleioblastus argenteostriatus leaves appeared an increasing and then declining trend especially K4. The results showed that the contend of Chlorophyll b of Pleioblastus kongosanensis f. aureostriaus and Pleioblastus argenteostriatus leaves appeared an increasing and then declining trend. Under the stress of the alkaline salt, the content of Chlorophyll a and b were not presented a single tendency, but the general trend was decreased.3.Studied on the effects of salt stresses on MDH of Pleioblastus argenteostriatus and Pleioblastus kongosanensis f. aureostriaus. Under the neutral salt stress, with the increasing of the salt concentration, the content of the MDH was increasing, especially Pleioblastus argenteostriatus. It showed that the membrane system was damaged by the salt stress. Under the stress of the alkaline salt, the results showed that the contend of MDH of Pleioblastus kongosanensis f. aureostriaus leaves appeared an increasing and then declining trend and then increasing, the membrane lipid per oxidation of leaves was the main factor to the damage of the cell structure and function.4.Studied on the effects of salt stresses on protective enzyme of Pleioblastus argenteostriatus and Pleioblastus kongosanensis f. aureostriaus. At the early stage of neutral salt stress, the activities of SOD and POD were increased and the damage of free radical was off set. At later stage of the stresses, the decreasing of SOD and POD activities indicated that the capacity of eliminating free radical was weakening. Under the stress of the alkaline salt, the change law of the SOD and POD activities was the same to the neutral salt stress.5.Studied on the effects of salt stresses on osmoregulation substance of the Pleioblastus argenteostriatus and Pleioblastus kongosanensis f. aureostriaus. Under the neutral salt stress, with the increasing of the salt concentration, the content of the proline was increasing and then sharp drop about the two kind bamboos. And under the K4 treatment, Pleioblastus argenteostriatus all dead. Under the stress of the alkaline salt, the change law of the proline was not uniformly. Under the neutral salt stress, with the increasing of the salt concentration, the content of the soluble protein was slowly increasing of Pleioblastus kongosanensis f. aureostriaus, but change law showed completely reverse trend about the soluble protein on Pleioblastus argenteostriatus. Under the stress of the alkaline salt, the content of the soluble protein was decreasing except for K1, and the part Pleioblastus kongosanensis f. aureostriaus dead under high salt treat. The change law was on the content of the soluble protein about two kind bambooss were the similar.6. Studied on the injured result of comprehensive evaluation under different alkaline and salt stress gradients. According to the analyzed on the all influence indexes by Subordination function method and evaluated and sorted damage degree of the two kinds bamboos according to the sixteen stress treatments.Results revealed that alkali salt stress and salt stress were actually two distinct kinds of stresses. The former was better called alkali stress, while salt stress only meant neutral salt stress. An interactive effect between salt stresses and alkali stresses could be found under mixed salt and alkali stress.