蘋果砧木綠枝扦插之發根生理

Physiological Studies on Rooting of the Apple Rootstock Softwood Cuttings

本研究之目的在比較蘋果砧木圓葉海棠（Malus prumfolia var. ringo）及EM Ⅶ（sub-variety of Malus pumila）商品種綠枝扦插發根之難易。並研究植物生長素- IB A（indole butyric acid）在發根過程中，對於插穗外部形態與內部生理變化之影響，其結果略如下：兩品種綠枝仟插，IBA處理者均較未處理者，發根迅速，發根率高，且發根數也多。在綠枝仟插發根過程中，圓葉海棠基部表皮先裂開再長根，仟插後第10天發根率可達50%；而EM Ⅶ插穗基部先長癒傷組織，再長根，第20天發根率達15%。在組織解剖土之研究，圓葉海棠基部切片於第6天即可在形成層與韌皮訊間發現根原體的產生；EM Ⅶ 則至14天尚無根原體之誘發。根原體誘發與發育期間，圓葉海棠插穗組織之生理變化為：澱粉含量在12天內（從仟插後第2天至第14天）迅速下降；可溶性醣與全氮含量之變化是先增後減，皆呈拋物線狀，前者第8天含量達到最高點，後者第6天之含量為最高；至於離層酸的含量則有逐漸下降之趨勢。E M Ⅶ方面之變化則為：澱粉含量在20天內（從扦插後第4天到第24天）緩慢下降；可溶性醣呈不規則形狀增加；全氮含量變化呈拋物線狀，至第8天含量達最高；離層酸含量則有逐漸上升之趨勢。

Comparison on rooting of softwood cuttings between two apple rootstock varieties, namely, easy-to-root 'Ringo' (Malus prunifolia) and difficult-to-root 'EM Ⅶ' (sub-variety of M. pumila). was made. Morphological changes as well as biochemical differences were detected during rooting after IBA-treatment. For both varieties, softwood cuttings treated with IBA rooted much earlier and more than those of the control. In 'Ringo' cuttings roots appeared after bark cracking, reaching 50% rooting in 10 days as compared with 15% in 20 days for 'EM Ⅶ' ' of which roots developed after forming callus at the base of cuttings. Root primordia was detected between cambium and phloem on the 6th day in the case of 'Ringo' as compared with no sign was shown up to the 14th day in 'EM Ⅶ'. The biochemical changes during rooting in 'Ringo' were as follows: 1). Starch content decreased rapidly starting from 2nd day through 14th day after the cuttings were planted; 2). Soluble sugar and total nitrogen content increased in the beginning and decreased thereafter. They reached highest point at the 6 th day and 8th day respectively; and 3). ABA content tended to decrease gradually. The EM Ⅶ were that: 1). Starch content decreased slowly within 20 days after they were planted; 2). Soluble sugar centent increased irregularly and total nitrogen content increased and reached maximum point on the 8th day after the cuttings were planted; and 3). the content tended to increase gradually.