Reversible conjugation of gibberellins in situ in maize.
Reversible conjugation of gibberellins in situ in maize.
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DOI：
10.1104/pp.73.2.340
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发表时间：
1983-10
期刊：
影响因子：
7.4
通讯作者：
S. B. Rood;R. Pharis;M. Koshioka
中科院分区：
文献类型：
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作者：
S. B. Rood;R. Pharis;M. Koshioka
在快速灌浆过程中，将赤霉素 [(3)H]GA(4)（1.33 居里每毫摩尔）和 [(3)H]GA(20)（2.36 居里每毫摩尔）注射到玉米（Zea mays L.）穗轴中，随后收获成熟种子。来自 1980 年饲料的成熟干燥种子提取物仅产生 20% 至 30% 的酸性、乙酸乙酯可溶形式的 (3)H 放射性，这主要与前体有关，主要代谢物 [(3)H]GA(1) 含量较少（基于连续 SiO(2) 分配和梯度洗脱反相 C(18) 高效液相色谱的假定鉴定） [高效液相色谱法]）。干种子中的大多数放射性与具有前体（GA（4）或GA（20））及其可能的主要代谢物（GA（1））的葡萄糖基缀合物的连续SiO（2）分配和反相HPLC的分配特征和联合色谱分析的化合物有关。大多数与前体 GA(4) 相关的缀合物与 GA(4) 葡萄糖苷同时洗脱。随后的酸或酶水解（β-葡萄糖苷酶或纤维素酶）产生游离 GA，假定的鉴定基于每个 (3)H 标记缀合物的等度 HPLC --> 水解 --> (3)H 标记水解产物的等度 HPLC。种子吸胀后，与缀合物部分相关的放射性降低；与此同时，观察到游离[(3)H]GA 类化合物水平显着增加。尽管 GA 类物质和 GA-葡萄糖基缀合物类物质的具体比例随年份、杂交品种甚至同一杂交种的不同植物的不同而有很大差异，但这种“可逆缀合”（即种子成熟期间的表观缀合，随后在发芽期间释放 GA 部分）对于来自 2 个以上玉米杂交种的种子中的 [(3)H]GA(20) 是可重现的。 年。
Gibberellins [(3)H]GA(4) (1.33 Curies per millimole) and [(3)H]GA(20) (2.36 Curies per millimole) were injected into the shanks of maize (Zea mays L.) cobs during rapid grain filling and mature seeds were subsequently harvested. Extracts of mature, dry seeds from 1980 feeds yielded only 20 to 30% of the (3)H radioactivity in acidic, ethyl acetate-soluble form, and this was principally associated with the precursor, with lesser amounts of the major metabolite, [(3)H]GA(1) (putative identification based on sequential SiO(2) partition, and gradient-eluted reverse-phase C(18) high performance liquid chromatography [HPLC]). Most of the radioactivity in the dry seeds was associated with compounds having partition characteristics of, and co-chromatographing on, sequential SiO(2) partition and reverse-phase HPLC with glucosyl conjugates of the precursors (GA(4) or GA(20)) and their probable major metabolite (GA(1)). The majority of conjugate associated with the precursor GA(4) eluted coincidental with GA(4) glucoside. Subsequent acid or enzymic hydrolysis (beta-glucosidase or cellulase) yielded the free GAs, putative identification being based on isocratic HPLC of each (3)H-labeled conjugate --> hydrolysis --> isocratic HPLC of the (3)H-labeled hydrolysate. Upon imbibition of the seeds, radioactivity associated with the conjugate fraction decreased; concomitantly, statistically significant increases in levels of free [(3)H]GA-like compounds were observed. Although the specific ratios of GA-like and GA-glucosyl conjugate-like substances varied substantially across years, hybrids, and even, in different plants from the same hybrid, this ;reversible conjugation' (i.e. apparent conjugation during seed maturation followed by release of the GA moiety during germination), was reproducible for [(3)H]GA(20) in seed from two maize hybrids produced over 2 years.