【作者】 廖文燕；

【导师】 高捍东；

【作者基本信息】 南京林业大学 ， 森林培育， 2011， 博士

【摘要】 本项研究以金钱松[Pseudolarix kaempferi (Lindl.) Gord]种子为材料,采用人工加速老化的方法探索种子的劣变过程,采用种子超干燥技术和低温贮藏相结合的方法研究种子在贮藏过程中的生理生化变化。主要结论如下：1、采用室温硅胶干燥法脱水速率较慢。除MC=3.3%的种子发芽率和活力指数显著低于MC=16.0%的种子以外,各含水量的种子发芽率、活力指数以及幼苗干重与MC=16.0%的种子相比没有明显差异。2、在50℃下人工老化后,4.2%≤MC≤5.3%的种子劣变速率最小；电导率随老化时间的延长、种子含水量的升高而增加；O2·-与丙二醛含量随老化时间的延长而增大；在种子活力未严重受损之前,SOD和POD的活性随老化时间的延长显著升高。3、室温下MC=16.0%种子(CK)ABA含量在贮藏180d内迅速下降,随后变化很小；IAA含量先逐渐升高再保持稳定；GA3含量先升高后下降；ZR含量在贮藏180d显著升高,随后先迅速降低再升高。GA/ABA比值比其他处理的种子要低,先升高后降低；IAA/ABA比值明显高于其他处理的种子,在贮藏期间持续增加；ZR/ABA比值先升高,180d后下降,至270d后又再次升高；(GA+IAA)/ABA比值的变化与IAA/ABA比值变化相似。4、低温贮藏的种子ABA含量缓慢上升；IAA含量在较低的水平上不断变化；GA3含量与ZR含量的变化与CK相似,但是变化幅度较小。GA/ABA比值虽然也是先升高后降低,但是在180d前后的变化幅度大,该比值明显高于CK; IAA/ABA比值在180d前后出现最大值,此后呈波动变化；ZR/ABA比值变化则没有明显规律；(GA+IAA)/ABA比值在270d前先升高后降低,270d后该比值保持在较低水平。5、4.2%≤MC≤6.4%的种子在5℃冷库中能够保持较高的发芽率和活力指数,其中以MC=4.2%的种子贮藏效果最佳；在-5℃下,5.3%≤MC≤6.4%的种子发芽率最高,MC=6.4%的种子活力指数最高,以5.3%≤MC≤7.5%的种子贮藏效果最好。在-5℃下贮藏的种子电导率变化总体趋势与在5℃下相似,但是前者的电导率升高幅度较小。6、贮藏期间种子可溶性糖含量和淀粉含量下降；可溶性蛋白含量总体上随贮藏时间的延长、含水量的降低而升高；粗脂肪含量变化规律不明显,各处理之间没有显著差异。7、种子在贮藏期间的O2·-含量持续升高,基本上随着含水量的降低而下降；丙二醛含量随贮藏时间的延长、种子含水量的升高而增大,增加幅度随种子含水量的升高而增大。在5℃下,5.3%≤MC≤6.4%的种子02-和丙二醛含量都是最低的；在-5℃下,MC=4.2%的种子O2·-含量最低,4.2%≤MC≤6.4%的种子丙二醛含量最低。在-5℃下贮藏的种子游离脯氨酸含量水平高于5℃下贮藏的种子。8、种子在贮藏期间的SOD和POD活性的差异都达到显著水平。超干种子的SOD活性呈明显升高的趋势,而且升高幅度随着种子含水量的升高而增大；POD活性则是呈先升高再降低的趋势。9、随贮藏时间的延长,胚乳细胞超微结构被破坏。超干燥处理和低温贮藏可以延缓细胞的衰老。MC=3.3%的种子细胞质浓稠,至贮藏末期有些细胞的结构完全降解消失。更多还原

【Abstract】 A study was conducted to the seed storage of P. kaempferi. Artificial accelerated aging has been used to probe the process of seed deterioration, and the method that integrated ultradry storage technology with low temperature storage has been used to investigate physiological and biochemical changes in seed storage. The main results were described as follows:1. Dehydration rate was smaller than other species by using silicone at room temperature. There were no significant differences between seed of MC=16.0% and seeds of 4.2%≤MC≤11.4% in germination percentage, seed vigor index and seedling dry weigh. However, significant differences were showed in both germination percentage and seed vigor index when MC declined to 3.3%.2. During artificial accelerated aging at 50℃, seed of 4.2%≤MC≤5.3% showed the minimal deterioration rate; seed conductivity was increasing when the aging time prolonged and the MC increased:the contents of both O2·- and MDA increased accompanied by the extension of aging time; and the activities of SOD and POD increased accompanied by the extension of aging time when the seed viability was not severely damaged.3. When seed of MC=16.0% stored at room temperature (CK), the content of ABA decreased sharply in the first 180 days and then remained stable; the content of IAA decreased slowly during the early storage time and then remained stable; the content of GA3 increased at first and then decreased; the content of ZR increased notably in the first 180 days, then decreased rapidly and increased steadily in the end. The ratio of GA/ABA was lower than the seed of other treatments and was increasing at first and then decreased. The ratio of IAA/ABA was higher than the seed of other treatments and was increasing steadily. The ratio of ZR/ABA increased during the first 180 days, then decreased before 270 days and increased in the end. The change of (GA+IAA)/ABA ratio was similar to the ratio of IAA/ABA.4. When the seed stored at low temperatures, the content of ABA increased steadily; the content of IAA was constantly changing at a low level; changes of the contents of both GA3 and ZR were similar to CK, however, the amplitudes were smaller. The ratio of GA/ABA was significant higher than CK and was increasing at first and then decreased which expressed large amplitude before and after 180 days. The ratio of IAA/ABA showed the maximum before and after 180 days, and then changed frequently. There was no regular pattern for the ratio of ZR/ABA. The ratio of (GA+IAA)/ABA was increased during 0～180 days and decreased during 180～270 days, then remained stable at a low level in the end.5. Seed of 4.2%≤MC≤6.4% retained higher germination percentage and seed vigor index at 5℃. Seed of MC=4.2% showed the best storage effect at 5℃. The germination percentage of seed of 5.3%≤MC≤6.4% was the highest, and the seed vigor index of MC=6.4% was higher than the seed of other MCs at -5℃. Seed of 5.3%≤MC≤7.5% showed the best storage effect at-5℃. The conductivity change of the seed stored at -5℃was similar with the seed stored at 5℃, while, the former amplitude was smaller.6. The contents of soluble sugar and starch decreased during the seed storage; and the content of soluble protein increased accompanied by the extension of storage time and the decline of MC. However, the content of crude fat showed no regular pattern and there was no significant difference among different treatments.7. The content of O2·- increased steadily during the storage, and this content in the mass decreased accompanied by the decline of MC; the content of MDA increased accompanied by the extension of storage time and the decline of MC, meanwhile, the amplitude increased accompanied by the rise in MC. At 5℃, the contents of both O2·- and MDA were the smallest with the seed of 5.3%≤MC≤6.4%. At -5℃, the content of O2·- with the seed of MC=4.2% was the smallest and the content of MDA with the seed of 4.2%≤MC≤6.4% was the smallest. The content of free proline of the seed stored at 5℃was smaller than the seed stored at -5℃.8. There were significant differences for the activities of both SOD and POD among different seed moisture contents during seed storage. The activity of SOD increased obviously in the ultradried seeds and the amplitude was increasing accompanied by the rise in MC. The activity of POD was increasing at first and then declined in the ultradried seeds.9. Accompanied with the extension of storage time, structure of albuminous cells was damaged. Ultradry and stored at low temperature could relieve consenescence of cells. The cytoplasm of seed of MC=3.3% became thick and the protoplast was degraded in some cells which left only overlapping cell walls by the end of seed storage.更多还原