胡枝子冬芽促萌及萌芽扦插技术研究

Study on the germination of winter buds and the techniques for sprouts cutting propagation of Lespedeza bicolor

摘要:

【目的】促进胡枝子平茬废弃枝条的利用,提高胡枝子扦插繁殖系数。【方法】将1年生硬枝切成段,在温室内进行冬芽促萌;采用完全随机区组设计研究促萌方式、瓶插枝段长度对枝段上冬芽萌生的影响。萌芽长出后,取萌芽进行扦插,采用完全随机区组设计研究萌芽长度、萌芽扦插培养基质、基质消毒方式对萌芽扦插生根的影响。采用L₉(3⁴)正交设计研究植物生长调节剂(ABT、NAA、IBA),浓度(250、500、750 mg/L)及处理时间(5、10、15 min)形成的9种不同处理组合对胡枝子萌芽生根的影响。【结果】1)胡枝子冬芽促萌时,可以将枝条剪切成10 cm枝段,基部用生长素处理或直接扦插到纯蛭石或干净河沙基质上,也可以将枝条剪切成枝段,插入20 mg/L GA₃的溶液中,这些方法能获得较高的萌芽率及插穗获得率;2)用250 mg/L植物生长调节剂NAA、IBA、ABT处理枝段后插入蛭石基质上,对冬芽萌芽率及插穗获得率的影响与直接扦插到蛭石基质上的影响相同;3)瓶插枝段长度影响冬芽萌芽率及插穗获得率;当枝段长度在10~40 cm范围内,枝段越长,冬芽萌芽率及插穗获得率越低,以10 cm表现最好;4)扦插基质的消毒方式影响萌芽扦插生根率,用0.1%多菌灵消毒显著优于用0.1%的百菌清或高锰酸钾消毒;5)萌芽长度影响扦插生根,长度越长,生根率越高,而且根系也越长,但是对分化的根系数量无影响;萌芽扦插时,适合选用4 cm以上萌芽作为插穗;6)萌芽扦插时,以插入纯蛭石基质上生根率最高,插入含有草炭土的基质则会显著降低扦插生根率,插入纯草炭土上不生根;7)正交试验的结果表明,以250 mg/L的NAA处理5 min,萌芽插穗生根率最高,生根率达到70%;8)对胡枝子进行硬枝扦插、嫩枝扦插和萌芽扦插,以萌芽扦插繁殖系数最高,能够达到49.98;萌芽扦插繁殖系数是硬枝扦插的3.6倍,是嫩枝扦插的1.7倍。【结论】对胡枝子进行萌芽扦插,既可以对胡枝子废弃枝条进行合理利用,还是一种比较好的扦插繁殖方式。

Abstract:

【Objective】To Promote the use of waste branches of Lespedeza bicolor and to increase the propagation coefficient of cutting.【Method】One-year-old hardwood branches were cut into segments before April, and their winter buds were forced to germinate in a greenhouse. Using a completely randomized block design, we examined the effects of germination-forcing method and of branch length (in the vase stage) on bud germination. The germinated buds were then used as cutting material. A second completely randomized block design was used to assess the effects of sprout length, cutting medium, and medium disinfection method on rooting. An L₉(3⁴) orthogonal design was used to evaluate the effects of plant growth regulator type (NAA, IBA, ABT), concentration (250 mg/L, 500 mg/L,750 mg/L), and treatment duration (5 min, 10 min, and 15 min) on rooting of L. bicolor sprouts.【Result】1) During winter-bud germination, germination rate and cutting yield were increased when branches were cut into 10 cm segments and either treated with auxin, directly inserted into the pure vermiculite or clean sand medium, or cut into segments and placed into 20 mg/L GA₃ solution. 2) After treatment with 250 mg/L NAA, IBA and ABT, the cuttings inserted into vermiculite gave the same winter-bud germination rate and cutting yield as those directly cut into the medium without regulator treatment. 3) Branch length at the vase stage affected both the germination rate of winter buds and cutting yield: within the 10~40 cm range, longer branches produced lower germination rates and yields, with 10 cm branches performing best. 4) Rooting rate was affected by the medium disinfection method; disinfection with 0.1% carbendazim was significantly more effective than those with 0.1% chlorothalonil or KMnO₄. 5) Sprout length affected rooting: longer sprouts gave higher rooting rates and longer roots but did not affect the number of differentiated roots. Sprouts longer than 4 cm were most suitable as cuttings. 6) Rooting rate was highest in pure vermiculite, was significantly reduced in media containing turf soil, and reached zero in pure turf soil. 7) The orthogonal test showed that rooting rate was the highest-up to 70%-when treated with 250 mg/L NAA for 5 min. 8) The propagation coefficient of sprout cutting (49.98) was the highest among the methods tested, 3.6 times that of hardwood cutting and 1.7 times that of softwood cutting.【Conclusion】Sprout cutting not only makes reasonable use of discarded L. bicolor branches but is also a more effective propagation method.