A Preliminary Study On Low Temperature Germination And Flowering In Gagea Nigra L. Z. Chue

Gagea nigraL. Z. Shue., a perennial early-spring ephemeral plant belongs to Gagea Salisb(Liliaceae),The flora of Xinjiang includes 13 species of the genus Gagea Salisb, and can often be found in the desert or the shade.Using the melting snow water in the early spring, Gagea Salisb can form flower buds under the frozen soil, Is the first flowering plants in northern xinjiang, then blossom under low temperature, and finish the life history quickly in 1-2 months,But the laboratory study is less, more confined to the field sampling and observation.Therefore, to obtain seed germination conditions in laboratory to G. nigra L. Z. Shue.As the research object to establish a good experimental basis, and provide the required materials to lay the foundation. And successfully obtain its flowering related genes, for further study of G. nigra L. Z. Shue.Under dark ice flower bud formation, able to complete their entire life history under low temperature environment will be of great significance.The main research results are as follows:(1)According to different mechanisms of dormancy, seed of Gagea nigra L.Z. Shue were treated with different methods so as to investigate the effects of different treatments on seed germination of G. nigra.The results showed that: begin to grow by 4 ℃ 32 days, Germination period of about 80 days, Germination rate of 72%; 25 ℃room temperature and acid treatment is not germinate;There had no significant difference by 50 ℃ warm water, ultrasonic and 200 mg / LGA3 treatment(P> 0.05); Extremely effective in promoting germination by remove the seed coat(P = 0.002 <0.01), Germination rate of 88%; Pierce the testa + 200 mg / LGA3 and 500 mg / LGA3 + 15% H2O2 treatment is also effective in promoting germination(P <0.05), Germination rates were 84%, 82%, former best germination potential, significantly higher than other treatments.(2)To obtain the 841 bp of FLOWERING LOCUS T(FT) gene(GeneBank: KT245135), by homology-based cloning and RACE technology encoding 178 amino acids, and found that it does not contain intronsby means of DNA sequence alignment.Structure domain forecast G.nigra FT gene has typical PBPstructure domainas PEBP gene family, after comparing found their site is different from other species, key amino acids encoded protein relative molecular weight of 20.104 KD, isoelectric point(pI) 7.63, formula for C885H1383N257O258S11; Secondary structure prediction shows that it has 5 alpha helix, 5 beta- fold, 16 beta around the corner.And build theplant expression vector of pMON530-FT-Gn.(3)Tostudy the FT gene affects the G.n igra flowering expression pattern by fluorescence quantitative rt-pcr technology, the results showed that: Firstly, similar to other plants, GnFT showed its maximum level in leaves. Secondly, GnFT expressed extremely high at ice stage and fruit stage, rather than at flowering stage in other plants. Thirdly, GnFT displayed high expression in all tissues at fruit stage.Based on the results of the study, on the condition of low dark leather processing and GA3 method of pretreatment to break G.n igra dormancy has significant effect, can effectively improve the germination rate and germination potential; For G.n igra in cold dark conditions forming bud main reason may be induced the GnFT gene expression, rather than the light conditions, moreover GnFT may also be involved in the formation of the bulb and fruit development.