| In this paper, to study the impact of drought stress on the seed germination of buckwheat and seed germination characteristics among differences varieties, it was taken14different buckwheat varieties for experimental materials and6concentration of PEG-6000(CK,5%,10%,15%,20%,25%) for stimulating drought environment; meanwhile we used six drought tolerance varieties selected by different germination characteristics to study the physiological characteristics and adaptability in seedling of different varieties under drought stress. The main results are as follows:1. Different PEG concentration have different effects on germination of buckwheat seeds. With PEG concentrations increasing, relative germination rate of seeds, germination potential, radicle length, plumule length, radicle/plumule and germination index decreased. In low PEG concentration (5%-10%), the change of these indicators had no significant difference, but compared with the control group, radicle length, germ length, germination index decreased significantly and reached a significant level in intermediate concentration (15%-20%). High concentration (25%) of PEG had a strong inhibitory effect on seed germination, it reduced the relative germination rate, germination potential and germination index, these items in25%concentration were only about0.5times in5%concentration.2. It had differences in germination characteristics among different varieties at the same stress conditions. It was the highest for relative germination rate and germ length of the YS in low concentration (5%). Compared with the WS, this two items respectively had9%,1.29cm higher, and different varieties had no significant differences. It was25%,10.21cm,1.64,2.8in germination potential, radicle length, radicle/plumule, germination index between the highest and the lowest in the different varieties. It was significant difference for germination potential, radicle length, radicle/germand and these items had the same trend, the difference between the highest and the lowest varieties were12%,7.27cm,2.16,16%,4.68cm,1.83in the intermediate concentration (15%-20%). High concentration (25%), NQ had the highest relative germination rate, germination potential, germination index and TX had the lowest. The difference between the highest and lowest were25%,13%,3.1, while different varieties had differences but the difference was not significant.3. There are some differences in different drought stress. With time of drought stress increasing, the relative conductivity, chlorophyll, MDA, free proline, soluble sugar content raised, while the leaf relative water content and soluble protein content decreased gradually. Buckwheat seedlings could grow well in short-term drought, but long time drought would inhibit their natural growth. This inhibition showed in the plant height, the longer for the drought stress, the more obvious for the inhibition. These physiological indicators is a conciliation mechanism to the buckwheat resist drought stress, the trend in different stress time reflects the adaptability of different buckwheat varieties to drought stress.4. Different varieties had different physiological and biochemical characteristics in drought stress. NQ had the hightest leaf relative water content, free proline, soluble sugar, soluble protein, chlorophyll content at the0-day; GP had the lowest and these items respectively were0.814,2.56μg/g,18.36mg/g,103.13mg/g,0.962mg/g; Howere, GP had the hightest membrane permeability and MDA content, NQ had the lowerest, compered with NQ, this two items decreased0.1021,1.28μmol/g. the changes for all items in the process of drought stress had the same trend with the start stress in different varieties.5. In this paper, we detected the seed germination and seedling physiological characteristics of different buckwheat varieties and found that BZ, YS and NQ had greater drought resistance than other varieties, it is worth for production and application. |
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