IBA浓度、扦插时间对江西杜鹃和百合花杜鹃扦插生根的影响

Effects of IBA concentration and cutting time on rooting ofRhododendron kiangsiense and Rh. liliiflorum cuttings

关键词:  江西杜鹃, 百合花杜鹃, IBA浓度, 扦插时间, 生根效果

Key words:  Rhododendron kiangsiense, Rh. liliiflorum, IBA concentration, cutting time, rooting effect

摘要:

为探明有鳞大花亚组杜鹃扦插生根的最佳IBA浓度和扦插时间,该研究以江西杜鹃、百合花杜鹃为材料,分别采用腐叶土+河沙(1:1)、泥炭+珍珠岩+蛭石(3:1:1)基质,开展了4个IBA浓度和4个扦插时间的生根试验。结果表明:IBA浓度对除老叶留存数外的所有指标有显著影响,其中100 mg·L^-1 IBA处理生根率、新梢长最大,腐烂率最低,其它指标也表现良好,为最佳生根浓度; 50 mg·L^-1 IBA处理根幅、新梢率最大,但不定根数最少,效果其次; 200 mg·L^-1 IBA处理促进根系生长,但生根率较低、特别是显著抑制新梢发育; 对照处理生根效果最差。扦插时间对所有生根指标均有显著影响,早春(04-18)木质化硬枝扦插除老叶留存数较差外,其它指标均表现极佳,为最适扦插时间; 秋季(10-19)半木质-木质化过渡枝扦插效果其次; 夏季(06-21)嫩枝及(08-16)半木质化枝生根效果极差,不宜进行扦插育苗。物种、基质对生根指标也有显著影响,百合花杜鹃扦插生根能力强于江西杜鹃,泥炭+珍珠岩+蛭石(3:1:1)基质生根效果优于腐叶土+河沙(1:1)。该研究结果首次发现早春新梢萌发前采用木质化硬枝扦插可以显著提高两种杜鹃的生根效果,为该亚组杜鹃的扦插育苗提供了科学依据。

Abstract:

To find out the best IBA concentration and cutting time for rooting of Rhododendron subsect. Maddenia(Hutch.)Sleumer cuttings, we studied the effects of four IBA concentrations and four cutting time on rooting of cuttings of Rhododendron kiangsiense and Rh. liliiflorum, using soil + sand(1:1)and peat + perlite + vermiculite(3:1:1)as rooting media. The results showed that IBA concentration had significant effects on most parameters except for retention number of old leaves. Cuttings treated with 100 mg·L^-1 IBA had the highest rooting rate and length of new shoot and the lowest rotting rate, with good performance of other parameters, and that was the optimum IBA concentration for rooting. Followed by 50 mg·L^-1 IBA, cuttings had the highest root width and new shoot rate but the lowest number of adventitious root. The solution of 200 mg·L^-1 IBA could promote the development of root, but it gave a low rooting rate and significantly inhibited the development of new shoot. The contrast had the worst effects on rooting. Cutting time had significant effects on all rooting parameters, and early spring(April 18th)with hardwood cuttings was the optimum cutting time, which gave excellent effect on most parameters except retention number of old leave, followed by autumn(October 19th)with cuttings transforming from semi-hardwood to hardwood. And summer with softwood cuttings(June 21st)or semi-hardwood cuttings(August 16th)had the worst effects, so that was not suitable for cutting propagation. Species and rooting medium also had significant effects on rooting parameters, such as Rh. liliiflorum had better rooting capacity than Rh. kiangsiense, and peat + perlite + vermiculite(3:1:1)was better than soil + sand(1:1). This study found for the first time that using hardwood cuttings in early spring before new shoots sprouting could significantly promote rooting of these two species cuttings, and that provides the information for cutting propagation of Rhododendron subsect. Maddenia species.