不同处理对凤丹种子萌发的影响

为研究不同处理对凤丹Paeonia ostii种子萌发的影响，采用穴盘育苗的方法，研究不同质量浓度赤霉素（GA₃，0，100，200，300 mg·L-1）结合不同温度（10，15，20℃）的处理对凤丹种子生根的影响，不同主根长（根长1~5 cm，根长＞5 cm）对生根种子萌发的影响，不同低温处理时间（15，30，45，52 d）对已生根种子萌发的影响以及下胚轴最膨大处直径和侧根数量对根长＞5 cm种子萌发的影响。结果表明:20℃结合300 mg·L-1 赤霉素（GA₃）处理，最有利于凤丹种子生根；对已生根种子4℃低温处理52 d后萌发率最高，达到84%，但耗时过长，且与低温处理30 d的萌发率差异不大，故30 d的低温处理是打破已生根凤丹种子上胚轴休眠的最佳方法；当穴盘透气不良时，根长小于5 cm的种子易腐烂，根长大于5 cm的种子极少有腐烂现象，且根长大于5 cm的种子移入温室60 d时，萌发率达到80%，远高于根长＜5 cm的种子萌发率；在同一处理条件下，生根种子下胚轴最膨大处直径大于3.0 mm或侧根数量大于10根时，上胚轴可优先萌发。图4表3参14

Seed germination of Paeonia ostii with GA3 and temperature treatments

To determine the effects on seed germination and rooting rate of Paeonia ostii, gibberellic acid (GA₃) (concentrations of 100, 200, and 300 mg·L-1) and temperature (10, 15, and 20℃) treatments were applied to P. ostii seeds in plugs. The effects on germination of rooted seeds was tested for length of the main root (1-5 cm and more than 5 cm) and low temperature treatment times (15, 30, 45, and 52 d). The relationships for hypocotyl diameter at its greatest point, total lateral roots of rooted seeds, and germination time were studied. Results showed that 20℃ combined with 300 mg·L-1-GA₃ was significantly different from other treatments for root development of P. ostii(P < 0.05). Seed took root after 30 d, and the seed rooting rate reached 92% after 100 d. Also, the proportion of seed whose root length was more than 5 cm reached 92%, and 4℃ for 30 d was the best treatment to release epicotyl dormancy with rooted seeds. Low temperature treatment for 52 d had the highest germination rate (84%), whereas low temperature treatment for 30 d had a similar germination rate(81%). The main root with a length of more than 5 cm broke epicotyl dormancy effectively with a high germination rate of 80.7% and low rotten seed rate. For the same treatment, epicotyls germinated first if the rooted seed hypocotyl diameter at the greatest point was more than 3.0 mm or if the total for lateral roots was more than 10. However, the hypocotyl diameter at the greatest point had little impact on lateral roots(correlation coefficient is 0.4). As the hypocotyl diameter at its greatest point increased and as the lateral root number increased, germination time shortened from 51 d to 24 d.Ch, 4 fig. 3 tab. 14 ref.]