Preliminary Studies On Evolution And Origin Of Halophyte Based On Six Species Of Limonium In Inner Mongolia

There are six species of Limonium distributed in inner mongolia,they are Limonium sinense(girard) kuntze.,Limonium bicolor(bunge) kuntze.,Limonium tenellum(turcz.) Kuntze.,Limonium flexuosum(linn.) Kuntze.,Limonium aureum (linn.) Hill.) And Limonium gobicum ik.According to the habitate,they could be divided into two types—xerophyte and halophytes.L.sinense is halophyte;L.aureum is salt-tolerant xerophyte;L.bicolor is xerophyte,it can be able to adapt to mild soil salinity;L.flexuosum,L.tenellum and L.Gobicum are xerophytes.In this research,the evolution of Limonium and the origin of xerophyte was studied by three methods of molecular biology,physiology ecology and numerical taxonomy.The conclusions are as follows:1.The phylogenetic tree show that L.flexuosum was divided from others first, followed by L.aureum(z).The other limonium was divided into two groups.One group consist of L.bicolor,L.gobicum,L.aureum(p),another group include L.sinense and L.tenellum.2.The result of numerical taxonomy show that L.flexuosum have lots of differences from others.It was separated at first,the others were divided into two groups,the L.sinense.and L.bicolor clustering together as a group,another group is composed of L.aureum(p),L.aureum(z) and L.tenellum.3.Under the drought stress conditions,I determined some physiological index of five species of limonium,and compare the ability of their drought resistance.The gradation of drought resistance was as follows:L.Jlexuosum > L.aureum(p) = L.aureum(z)> L.bicolor> L.sinense.4.I arranged five salinity gradient and measured some physiological index under the salitiny stress conditions,such as chlorophyll,proline,membrane protective enzymes,MDA and soluble protein content.Through the comprehensive evaluation of all physiological index,the ability of salt-tolerant was as follows:L.sinense.> L.aureum(p)> L.aureum(z)> L.bicolor > L.flexuosum.To sum up the above conclusions,we conjecture that halophytes is likely to originated from xerophyte.In this paper,several species of Limonium was used to study the evolution relations between halophytes and xerophyte,it may provide a research approaches on specialization of plant functional.