Effects Of Drought And Salt Stress On Physiological And Biochemical Characteristics And Ornamental Quality Of Rose

?Objective?Chinese rose is one of the main flower plants used in landscape green system in Xinjiang.Due to the great difference of climatic environment and geographical conditions between Xinjiang and the introduced place,the varieties of Chinese rose introduced from the inland often cannot well adapt to the environmental conditions in xinjiang,which results in the waste of seedlings.Therefore,the rose varieties,which were of better performance on physiological and biochemical characteristics and ornamental quality,were selected after drought stress and salt stress to provide theoretical reference for the introduction of Chinese rose into Xinjiang.?Method?Drought tolerance tests were carried out as followed:CK,drought resistance test at 80%?CK?,65%,50%,35%maximum field water capacity.Salt tolerance tests were conducted at concentrations of 0.1%?0.2%?0.4%?0.6%and 0.8%salt concentration?NaCl:Na₂SO₄=1:2?.Two year old seedlings of four large-flower rose varieties and four abundant-flower rose varieties were employed in the above experiments.The morphology,activity of antioxidant enzyme system,permeability of plasma membrane,osmotic regulation and photosynthetic index of flowering phase were measured.Two-factor analysis of variance was used to analyze the difference of drought tolerance and salt tolerance,and principal component analysis was further used to carry out comprehensive evaluation of physiological and biochemical characteristics and ornamental quality after drought tolerance and salt tolerance treatments,and finally selected rose varieties with good resistance.The single factor analysis of variance was carried out on the selected Chinese rose varieties with good tolerance to explore the effects of drought stress and salt stress on their physiological,biochemical and ornamental indexes.?Result??1?The different Chinese rose varieties showed different drought tolerance under the drought stress.Ornamental indexes of each rose variety firstly decreased and then rose.Drought stress inhibited photosynthesis and decreased chlorophyll content?Tr?Gs?Pn?Fv/Fm?Y?II??and qP,and increased Ci?qN and Y?NPQ?.Drought stress increased the antioxidant enzyme activity and osmotic substance content in large-flower Chinese rose varieties and abundant-flower Chinese rose varieties to some degree,whereares,the change trends of enzyme activity and osmotic regulatory substances in large-flower Chinese rose varieties and abundant-flower Chinese rose varieties were different with the drought degree.The 65%MFWHC treatment was favorable for the growth of all introduced Chinese roses.?2?Based on principal component analysis,the drought-tolerant order of large-flower rose varieties was as followed:‘Tineke'>‘Powder fan'>‘Holiday fireworks'>‘Hiogi';The drought tolerance of abundant-flower rose varieties was as followed:‘Yellow Leisure Liness'>‘Moheim'>‘Red Leisure Liness'>‘Gentle'.?3?The comprehensive character different rose varieties showed different salt tolerance ability.The morphological indexes of each rose variety under salt stress decreased.It inhibited photosynthesis and reduced chlorophyll content?Tr?Gs?Pn?Fv/Fm?Y?II?and qP,and increased Ci?qN and Y?NPQ?.The salt stress increased the antioxidant enzyme activity and osmotic substance content in large-flower Chinese rose varieties and abundant-flower Chinese rose varieties to some extent,but with the increase of salt concentration,the change trend of was different in the introduced rose varieties.The large-flower rose varieties and the abundant-flower rose varieties had some adaptability and buffering ability to the salt concentration below 0.2%.?4?Based on principal component analysis,the salt-tolerant order of large-flower rose varieties was as followed:‘Tineke'>‘Powder fan'>‘Hiogi'>‘Holiday fireworks';The salt-tolerant tolerance of abundant-flower rose varieties was as followed:‘Moheim'>‘RedLeisure Liness'>‘Gentle'>‘Yellow Leisure Liness'.?Conclusion?Different rose varieties had different stress tolerance mechanisms and different stress tolerance.A single index should not be used as a standard to evaluate drought tolerance and salt tolerance of introduced Chinese rose varieties,and multiple indicators should be comprehensively analyzed.Through principal component analysis,it was seen that the salt tolerance and drought tolerance of‘Tineke'and‘Powder fan'were better in big flowering rose varieties.The salt tolerance and drought tolerance of‘Moheim'in fenghua rose varieties were better than others.