Seed Biology Of 72 Wild Orchid Species In Fujian Province And Molecular Identification Of Dendrobium Loui

There are more than 160 species of Orchidaceae in Fujian province.The life-form of wild orchids are mainly in terrestrial,and the epiphytic orchids are also abundant.Based on the systematic investigation of background resources in Fujian province,the research on seed biology of wild orchids were carried out.In this paper,the morphological characteristics of mature capsules and seeds of 72 species of wild orchids from Fujian province and the viability of some seeds were determined.The non-symbiotic germination of Dendrobium wilsonii and Anoectochilus roxburghii,the molecular identification of a newly recorded species--Dendrobium loui in Fujian province,was further studied.The results supplemented the morphological characteristics of seeds of Fujian wild orchids and provided basic data for the taxonomy of Orchidaceae.The rapid propagation system of Dendrobium wilsonii and Anoectochilus roxburghii was established,which could provide reference for the formulation of conservation plan.In addition,molecular biological evidence was provided for the identification of Dendrobium loui.The main results are as follows:?1?Among 72 species of wild orchids investigated,different types of wild orchids have different morphological characteristics,Geophytic orchids are mainly oval,the fungi parasitic orchids are mostly rod-shaped,and the epiphytic orchids are mostly rod-shaped or droplet-shaped.There are a large number of small seeds in the capsule,but the capsules of the Vandeae also contain a large number of filaments.The number of different species of errestrial orchids seeds is quite different,such as the Neottia japonica with an average of 63±9 seeds,but the Cymbidium ensifolium with an average of 1,337072±202 411 seeds;the difference in the number of seeds of epiphytic orchid is less than the errestrial orchid,less,such as the Oberonia japonica with an average of 1 648±336 seeeds,more,such as the Robiquetia succisa with an average of 216 441±43 727seeds.The morphology of seeds of different species of wild orchids are diverse,mostly spindle or strip,some seeds are linear or spoon-shaped,the micropyle at the base cells.It is worth mentioning that both species of seeds of Lecanorchis are linear,with a net pocket in the middle.In general,the seed coat cells are arranged tightly and the lateral walls are thicker,the seed coat of epiphytic orchid is generally more closely arranged and the lateral wall of epiphytic orchid is thicker than that of terrestrial orchid.The intercellular gap is formed between the seed coat cells of the some of Neottieae seeds.The embryo has a transparent envelope,the color changes from colorless to brown,and there is no endosperm,but there are plastids in the embryo,and chloroplasts in a few species;Some species have suspensor,but most of them have only traces of suspensor degeneration,only a few of them can be seen.,which grow towards the micropyle at the base cells.and the suspensor of different species and genera have different morphological.In addition,6.94%of the species have polyembryonic.The volume of seeds of Geophytic orchids change greatly,the largest,such as the Epipactis thunbergii the average can reach 33.761*10^-3 mm³,and generally smaller for Epiphytic orchid,usually below 1.0*10^-3 mm³.In general,the air cavity of the seeds of Geophytic orchid is larger,occupies more than 50%of volume of a seed?air cavity ratio?;the air cavity ratio of fungi parasitic orchids are more than 80%;and the air cavity ratio of epiphytic orchids are less than 50%.?2?TTC staining showed that the seed viability of wild orchids varied greatly among different species,and the lowest is 0,such as the Peristylus lacertifer,the highest is over90%,such as the Dendrobium moniliforme;The seeds of terrestrial orchids have viability,with an average viable of 52.02%;the viability of fungi parasitic orchids is 6%,All of the epiphytic orchids have viability,with an average viable of 60.55%.There is a correlation between embryonic rate and viability of seeds,and those with lower embryo rate have lower seed viability.?3?Under aseptic conditions,the seeds of Dendrobium wilsonii and Anoectochilus roxburghii could germinate,the pretreatment had a little effect on the germination of Dendrobium wilsonii seeds,while the seeds of Anoectochilus roxburghii were need pretreated to germinate.The propagation of Dendrobium wilsonii by the protocorm and the internode germination point on stem;the Anoectochilus roxburghii has multiple germination points on rhizome.The optimum growth medium for Dendrobium wilsonii is MS+activated carbon 2.5g/L+10%banana juice;the optimum proliferation and differentiation medium for Anoectochilus roxburghii is 1/4 MS+NAA 1.0 mg/L^-1+6-BA1.0 mg/L+10%banana juice,and the optimum medium for rooting and growth-promoting is 1/4MS+6-BA 1.0 mg/L-1+activated carbon 0.25g/L-1+10%banana juice.The ITS sequence of Dendrobium loui from Zhouning County of Fujian Province is more than 99.45%similar to that of D.loui in NCBI library.Combined with the morphological structure and plant morphology of the flower,the species is identified as D.loui.