Study On Physiological And Ecological Adaptability Of Three Species Of Melastomataceae

Melastomataceae have large showy flowers,high ornamental value,is the new international popular flowers,suitable for the popularization and application in the garden.The three species of Melastomataceae in this paper have high ornamental value and development potential.The development and utilization of plant resources is of great significance to enrich the types of garden plants and improve the quality of landscape.The research and application of the natural soil drought,the artificial low temperature environment,different shading treatment was carried out Melastoma malabathricum'Tianjiao',Tibouchina granulosa and Allomorphia eupteroton var.teretipetiolata of drought resistance,cold tolerance and shade tolerance research and analysis its application in gardens.The main results are summarized as follows:(1)According to the plant morphology,Melastoma malabathricum‘Tianjiao' and Tibouchina granulosa grow well in slight drough,plant morphology is not affected;Allomorphia eupteroton var.teretipetiolata grows well under moderate drought.Show that the drought tolerance threshold of Allomorphia eupteroton var.teretipetiolata was higher than that of Melastoma malabathricum‘Tianjiao'and Tibouchina granulosa.(2)Under drought stress,the determination of leaf relative conductivity,soluble sugar content,soluble protein content,proline content,physiological and biochemical indexes of MDA content,and the actual performance of plants under drought stress in the morphological and physiological characteristics were tested in three plants in mild to moderate drought and drought when plants did not change significantly.Under severe drought stress,and the control group were significantly different.With the increase of soil drought stress,the relative conductivity,MDA content a nd proline content of leaves of three plants showed a rising trend.The change of soluble protein content was not significant,soluble sugar decreased first and then increased.Through a comprehensive analysis of five physiological indexes are Allomorphia eupteroton var.teretipetiolata and Melastoma malabathricum 'Tianjiao' in the moderate drought when growth is good,Tibouchina granulosa grows well in mild drought.(3)After 0?-3h at low temperature,the leaves of the plants of all the three species of Melastomataceae showed browning and petiole drooping.With the increase of stress time,the survival rate of the seedlings decreased significantly At 5?,Melastoma malabathricum 'Tianjiao' and Allomorphia eupteroton var.teretipetiolata growth showed normal,stem angle of Tibouchina granulosa appear petiole sagging phenomenon after 24 h.The three plants grew well at 10? and Guangzhou winter without any persecution.(4)Under low temperature stress,The relative water content of leaves was insensitive to low temperature stress at 10?.The MDA content,soluble protein content and proline content of the 3 plants showed an upward trend compared with the low temperature stress the Melastoma malabathricum 'Tianjiao' and Allomorphia eupteroton var.teretipetiolata content of SOD increased,reached the maximum value at 5?-72 h,and the trend of Tibouchina granulosa at 5?showed decreased and reached the maximum value at 5?-48h(430.19 u.g-1).(5)In low light environments(shade 50%),to Melastoma malabathricum 'Tianjiao' and Tibouchina granulosa on the growth,biomass accumulation,leaf area and chlorophyll content increased,but decreased chlorophyll a/b;and Allomorphia eupteroton var.teretipetiolata showed the leaf area and chlorophyll a/b increased to promote the growth of seedlings,but.Reduce the content of chlorophyll;under full sunlight,net photosynthesis of three species of photosynthetic rate were higher,especially the Melastoma malabathricum 'Tianjiao' and Tibouchina granulosa.The former reflects(Melastoma malabathricum 'Tianjiao' and Tibouchina granulosa)and the latter on light adaptation interval between Allomorphia eupteroton var.teretipetiolata to adapt to wide range of light(6)The membership function analysis showed that under mild and moderate drought,drought resistant ability were Allomorphia eupteroton var.teretipetiolata>Melastoma malabathricum'Tianjiao' >Tibouchina granulosa;under heavy stress,Melastoma malabathricum'Tianjiao'>Allomorphia eupteroton var.teretipetiolata>Tibouchina granulosa.In general,Allomorphia eupteroton var.teretipetiolata and Melastoma malabathricum ‘ Tianjiao ' strong resistance to drought,and the drought tolerance of Tibouchina granulosa is weak,only suitable for growth of more than 50~55% in the habitat.From the cold resistant ability analysis,no matter in which low temperature treatment showed heyneana shaped wood,Allomorphia eupteroton var.teretipetiolata > Melastoma malabathricum'Tianjiao' >Tibouchina granulosa.O verall,Allomorphia eupteroton var.teretipetiolata and Melastoma malabathricum'Tianjiao' strong resistance to cold,they can grow at 3~5?;and Tibouchina granulosa cold resistance is weak,at 5? to grow well.(7)Survey results show Melastoma malabathricum'Tianjiao' compact plant type,since the spherical,in full sunlight,more than 3~5? of good growth,Showed strong drought resistance and cold resistance,suitable for potted plants,flower planting in garden application,or for isolated planting,planting in Road entrance,planted in the forest edge zone for isolation belt.;Tibouchina granulosa long flowering stem angle light,need,at 5~7? growth is good,the small tree height is 3m arond,can be planted in the water,or isolated planting,planted landscape trees do in sparse forest grassland;Allomorphia eupteroton var.teretipetiolata drought resistance,cold tolerance,3~5?,under full sunlight or under 50% shade growth good management is relatively extensive,can be planted,planted landscape trees in sparse forest grassland.