核桃早实品种微枝接穗试管扩繁技术的研究

Mini shoot Scion Proliferation in vitro of the Precocious Walnut Cultivars

以早实核桃新品种为试材，对试管微枝接穗扩繁中的主要技术环节进行了研究。结果表明：接种外植体适宜的时期为新梢长至８～１０个节位，适宜的取样部位为顶芽和顶芽下第４和第５个带节茎段。培养基中ＢＡ水平、培养温度和继代间隔时间对微枝产生的数量和质量有明显影响。ＢＡ为０．５～１．０ｍｇ／Ｌ，培养温度以昼夜变温即白天２５±３℃、夜间１８±２℃以及继代间隔２０ｄ为微枝扩繁的适宜条件。对生长势衰退的试管微枝进行去除顶端处理，可部分恢复其生长势，抑制衰老黄化和试管内开花。采用改良ＤＫＷ培养基显著增加了试管微枝生长势，基本上克服了退化现象的发生，是扩繁早实品种微枝接穗较好的培养基。

A technique for mass proliferating mini shoot scions in vitro of the prcocious walnut cultivars ( Juglans regia ) has been established. Tests on the proliferation were carried out and presented in this paper.The results showed that it was the suitable time to collect the shoot node explants in tree for in vitro culture when the shoots grew to form 8～10 nodes. The shoot tip and the fourth and fifth nodes under the shoot tip in the shoot had highest survival and germination rate after being sterilized and cultured in vitro. The proliferation rate and the quality of mini shoot scion was obviously influenced by th BA level in DKW medium,the temperature for culture and the proliferation subculture interval,and the best results were achieved when BA in the medium was 0.5～1.0 mg/L,changing temperature of 25±3 ℃ in day and 18±2 ℃ at night and 20 d interval of proliferation subculture.The treatment of cutting off the shoot tips (about 0.5 cm) of the deteriorated shoots clump could partly recover its growth vigor and inhibited its flowering in vitro.From our tests, a modified DKW medium was developed which could dismiss the deterioration phenomenon.After being applied in our lab,the modified DKW demonstrated a better medium for mass proliferation of the mini shoot scion of precocious walnut cultivars.