滇重楼种子内源激素含量与种胚长度和萌发的关系

[目的]通过研究滇重楼种子层积过程中不同阶段内源激素含量与种胚长度的动态变化情况来探讨种子休眠机理.[方法]应用酶联免疫吸附法测定不同阶段种子内激素含量.[结果]种子萌发过程中,脱落酸(ABA)含量由54.34 ng·g^-1·FW降至32.16 ng·g^-1·FW,赤霉素(GA)、玉米素核苷(ZR)显著升高,吲哚乙酸(IAA)含量波动较大,但整体呈逐渐升高趋势,随层积时间延长,未萌发种子中ABA含量持续降低,GA含量与GA/ABA值持续升高,仍显著低于已萌动种子中激素含量(p<0.05);种子在层积42天后,种胚开始膨胀,胚率快速增加;相关性分析结果,内源激素含量及比值与种胚生长呈显著相关(p<0.05),其中,GA/ABA值对种胚生长的影响最大.[结论]种子萌发过程中仅ABA含量降低不足以解除滇重楼种子休眠,同期GA含量升高和GA/ABA值达到某一阈值时能有效的解除滇重楼种子的休眠和促进胚的发育;种子在层积40天左右后,由于各项激素的综合作用,滇重楼种子由休眠状态逐步转变为破除休眠状态和萌发状态.

Relationship between Endogenous Hormone Content and Embryo Growth and the Seed Germination of Paris polyphylla var. yunnansensis

[Objective]To study the variation of embryo length and endogenous hormone content in seed during stratification so as to understand the dormancy mechanism of Paris polyphylla var. yunnansensis seed. [Method]The enzyme linked immunosorbent assay (ELISA) was used to measure the hormone contents of seed in various stages. [Result]The results showed that during the process of seed germination, the abscisic acid (ABA) content reduced from 54.34 ng·g^-1·FW to 32.16 ng·g^-1·FW, both the gibberellin (GA) and zeatin riboside (ZR) contents increased markedly, the indoleacetic acid (IAA) content fluctuated significantly, but increased gradually as a whole. With the extension of stratification time, the ABA content in the dormant seed reduced, while the GA content and the ratio of GA/ABA continued to rise, but they were still significantly lower than that in the germinating seed (p<0.05); the embryo began to swell 42 days after the seed was stratified, and the embryo rate increased rapidly; the correlation analysis showed that the endogenous hormone content and ratio was significantly correlated with the embryo growth (p<0.05), the impact of GA/ABA ratio on embryo was the largest. [Conclusion]The results suggest that reducing ABA content alone may not be enough to release the dormancy of P. polyphylla var. yunnansensis during seed germination, and the increasing of GA content and the GA/ABA ratio reaching to a certain threshold may be able to release seed dormancy and promote the development of embryo effectively. Due to the combination of the various hormones, the seed gradually entered the dormancy breaking state and germination state after 40 days' stratification.