The Adaptation Of Alpine Plant Crucihimalaya Himalaica To Water Stress

In Alpine areas,plants are often exposed to bad habitats and multiple environmental stresses.Especially in screen alpine southwest China,challenges from extreme temperature,great range of temperature in day and night,drought,rarefied air,strong irradiance,poor soil are obvious.Plants have to adapt to the changing environment,which results in special characters:Our previous study showed that Crucihimalaya himalaica(C.himalaica),a close relative of model plant Arabidopsis thaliana(A.thaliana),was more tolerant to extreme potassium deficiency.Drought is the main environmental stress for plants in nature,and plants will encounter physiological drought inscreen alpind.However,the mechanism of adaptation to water stress is still unknown,so it is great significance to study this mechanism of the environmental adaptability of plants.In this paper,the artificial control experiment of drought was set up on the water culture system of plant.The phenotypes,physiological and biochemical responses and gene expression patterns of C.himalaica drought stress were measured and compared with them of A.thaliana.The mechanism of adaptation to water stress was studied in this paper.The main results are as follows:First,under the drought stress,the wilting of C.himalaica was more serious than that of A.thaliana.The relative water content and chlorophyll fluorescence of C.himalaica were lower than those of A.thalianaa,which indicated that the drought tolerance of C.himalaica was lower than that of A.thalianaa.Second,under the drought stress with potassium-free,there has been no change in the ability of C.himalaica to withstand drought.,but the drought resistance of A thalianaa was decreased significantly.It was suggested that the response mechanism of C.himalaica to drought may be different from that of A.thalianaa,and the mechanism may be involved in its special tolerance to potassium deficiencyThirdly,comparing the expression patterns of proline synthesis and degradation related genes,it was found that the trend of proline accumulation in C.himalaica was lower than that in A.thalianaa,and the former was not affected by potassium deficiency,while the latter was affected by potassium deficiencyFourthly,the proline content of A.thalianaa mutant with proline synthesis gene p5cs1 knockoutwas significantly lower than that in wild type A.thalianaa,which are used to carried out drought and dorught with potassium-deficiency experiments,and we found that the phenotype of C.himalaica was similar to that of A.thalianaa mutants,but different from that of A.thalianaa wild typeThese results showed that the drought tolerance of C.himalaica was low,which was caused by the low proline accumulation ability of it.We speculated that this special mechanism of drought adaptation in C.himalaica may be related to the adaptive evolution of proline metabolism pathway in potassium deficient environment.