Physiological And Ecological Studies Of Brasenia Schreberi With Different Leaf Colors

There are rich leaf colors in nature,and differ from green leaves,red leaves have unique physiological and ecological functions.Brasenia schreberi J.F.Gmel is an endangered aquatic vegetable in China.On the field investigation,we discovered that B.schreberi leaves formed different colors on the underside of leaves,and the color of B.schreberi leaves in different areas are varied.The underside of B.schreberi leaves in Suzhou and Hangzhou is mainly red with different shades,while that in Lichuan and Shizhu is mainly green.In addition,Suzhou has a rare B.schreberi strain with edge-red leaves.In order to explore the origin,regulation mechanism and physiological as well as ecological functions of different colors on the underside of B.schreberi leaves,the following experiments were designed:(1)exploring the physiological causes of different leaf colors of B.schreberi,measuring the differences in the content and types of the pigment in B.schreberi;(2)exploring the molecular biological basis of B.schreberi different leaf colors,mainly through transcriptome sequencing of four kinds of B.schreberi;(3)studying the antioxidant capacity of B.schreberi different leaf colors and exploring the differences in physiological functions of B.schreberi different leaf colors;(4)exploring the differences in the adaptability of B.schreberi with different leaf colors to the environment through cultivation experiments with different water temperatures.The results showed that,anthocyanins are the main physiological reasons for the formation of dark-red,light-red,edge-red and green leaves of B.schreberi.As the anthocyanins content increases,the redder the leaves become.The anthocyanins in the four kinds of leaves were roughly the same,and the anthocyanins were determined to be derivatives of cyanidin by experiments.In four leaf color B.schreberi transcriptome data,the intraclass correlation coefficient and interclass correlation coefficient were similar.The number of differential gene between edge-red leaves and the other three leaf color is larger.The difference of anthocyanin content between dark-red leaves and edge-red,light-red leaves and edge-red leaves may be caused by the metabolic difference of phenylpropanoid biosynthesis pathway.All four leaf color B.schreberi have certain antioxidant ability,and their scavenging abilities of hydroxyl free radical and ABTS+free radical are all better than that of ascorbic acid(VC).In terms of anthocyanin concentration,the scavenging ability of hydroxyl free radicals ranged from strong to weak was edge-red leaves,light-red leaves,green leaves and dark-red leaves.In terms of leaf quality,the scavenging ability of hydroxyl free radicals ranged from strong to weak was edge-red leaves,light-red leaves,dark-red leaves and green leaves.In terms of anthocyanin concentration,the scavenging ability of ABTS+free radical ranged from strong to weak was green leaves,edge-red leaves,dark-red leaves and light-red leaves.In terms of leaf quality,the scavenging ability of ABTS+free radical from strong to weak was dark-red leaves,green leaves,light-red leaves and edge-red leaves.The photosynthetic parameters of the B.schreberi cultivated in a moderately heated pond(the heated group)were different from those cultivated in a pond with normal water temperature(the unheated group),but their pigment contents were not significantly different.In the unheated group,the photosynthetic capacity of dark-red leaves was significantly different from that of light-red leaves,the photosynthetic capacity of dark-red leaves is stronger,while in the heated group,the photosynthetic capacity of dark-red leaves was close to that of light-red leaves.The above study shows that the anthocyanins content of the cyanidin inB.schreberi affects the color of the underside of leaves.We speculate that the difference in anthocyanin content is mainly caused by the upstream phenylpropanoid biosynthesis pathway.The antioxidant capacity of B.schreberi leaves is strong,which can be fully utilized.B.schreberi with different leaf colors have different adaptability to the environment,under the experimental conditions,the dark-red leaves have better adaptability,and the light-red leaves are more sensitive to the change of temperature.