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Cytokinins from terminal buds of Euphoria longana during different growth stages
Author(s) -
Chen WenShaw,
Huang KuangLiang,
Yu HsiaoChing
Publication year - 1997
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1997.tb03447.x
Subject(s) - zeatin , cytokinin , glucoside , riboside , biology , purine , shoot , botany , chemistry , biochemistry , auxin , enzyme , medicine , alternative medicine , pathology , gene
The presence of endogenous cytokinins were detected in the terminal buds of longan ( Euphoria longana Lam.) after purification by ion exchange and Sephadex LH‐20 chromatography, and bioassay, enzymic degradation, high‐performance liquid chromatography and gas chromatography‐mass spectrometry. Permethylated derivatives of two highly active cytokinin glucoside compounds from dormant buds were: 6‐(4‐O‐β‐D‐glucosyl‐3‐methyl‐but‐2‐enylamino) purine (zeatin‐O‐glucoside) and 9‐β‐D‐ribofuranosyl‐6‐(4‐hydroxy‐3‐methyl‐but‐2‐enylamino) purine (zeatin riboside‐O‐glucoside). Simultaneously, four active cytokinins from buds at the stages of leaf flush and flower bud initiation were identified as 6‐(4‐hydroxy‐3‐methyl‐but‐ trans ‐2‐enylamino) purine (zeatin), zeatin‐9‐β‐D‐ribofuranosylpurine (zeatin riboside), 6‐(3‐methyl‐2‐butenyl) aminopurine (isopentenyladenosine, 2iPA) and N‐(3‐methyl‐2‐butenyl) adenine (isopentenyladenine, 2iP). The total cytokinin levels were low at leaf flush, with the zeatin and zeatin riboside in the buds about 70% of the total. In the transition of the terminal bud from leaf flush to dormancy, the principal cytokinins were zeatin‐O‐glucoside and zeatin riboside‐O‐glucoside. However, significant decreases in the levels of zeatin‐O‐glucoside and zeatin riboside‐O‐glucoside and increases in those of zeatin, zeatin riboside, 2iPA and 2iP were observed at flower bud initiation. It is suggested that in longan, the cytokinins that are translocated to the shoots are accumulated in the buds at the dormant stage, and that later there is a considerable increase in free cytokinins during flower bud initiation, leading to the promotion of flower bud development.