结实与不结实紫薇花芽发育形态及生理特性

Developmental morphology and physiological characteristics of the flower buds of fruiting and unfruiting Lagerstroemia indica

【目的】为进一步探讨紫薇Lagerstroemia indica结实与不结实的生理生化机制,为紫薇不结实机理提供理论依据。【方法】以结实与不结实紫薇5个时期的花芽为材料,利用扫描电镜和体视显微镜观察发育过程中花芽内外部形态变化特征,通过测定花芽发育过程中可溶性糖、可溶性蛋白、游离脯氨酸、超氧化物歧化酶活性、过氧化氢酶活性、过氧化物酶活性、丙二醛以及营养元素含量,分析紫薇花芽发育过程中的生理生化变化规律。【结果】时期Ⅰ两种紫薇子房突出,时期Ⅲ时胚珠外露,结实紫薇在时期Ⅲ时已开始长出花瓣和花丝,而不结实紫薇花瓣不明显。2种紫薇在花芽发育过程中可溶性糖含量均呈先上升后下降的变化趋势。时期Ⅲ时,不结实紫薇较结实紫薇可溶性蛋白含量降低了22%。不结实紫薇游离脯氨酸含量仅在时期Ⅰ时高于结实紫薇。除时期Ⅲ外,其他时期花芽的超氧化物歧化酶(SOD)活性均是结实高于不结实。不结实的过氧化氢酶(CAT)活性在花芽发育各阶段均显著低于同时期可结实的活性,不结实和结实的过氧化物酶(POD)活性呈相反的变化趋势。在花芽发育后期,结实的丙二醛(MDA)含量较低,而不结实丙二醛含量显著升高,结实与不结实花芽中营养元素的含量有较大差异。【结论】结实紫薇各个时期花芽横纵径大于不结实紫薇同时期花芽,结实紫薇在时期Ⅲ时已开始长出花瓣和花丝,而不结实紫薇花瓣不明显。不结实紫薇花芽的可溶性糖、可溶性蛋白含量均低于同时期的结实紫薇。糖类物质的亏缺可能导致小孢子的育性降低,导致紫薇花的雄性不育。不结实在花芽发育过程中游离脯氨酸积累较少。不结实紫薇的CAT代谢并不旺盛,丙二醛的持续积累可能是不结实败育的一个原因。不结实花芽发育过程中,可能由于各营养元素含量的不足,使与之相关的酶活性受到影响,最终使得花药的发育受到明显的影响。

【Objective】To further explore the physiological and biochemical mechanisms of Lagerstroemia indica fruiting and unfruiting,and to provide theoretical basis for the mechanism of L.indica unfruiting.【Method】The flower buds of 5 stages of fruiting and unfruiting L.indica were used as materials,and the characteristics of the internal and external morphological changes of flower buds during development were observed by scanning electron microscopy and stereopicroscope.By measuring the contents of soluble sugar,soluble protein,free proline,superoxide dismutase activity,catalase activity,peroxidase activity,malondialdehyde and nutrient elements in the process of flower bud development,the physiological and biochemical changes of L.indica in the process of flower bud development were analyzed.【Result】In stageΙ,the ovules of L.indica were prominent,the ovule was exposed in stageⅢ,and fruiting L.indica began to grow petals and filaments in stageⅢ.And the unfruiting L.indica was not obvious.The soluble sugar content of both L.indica species firstly increased and then decreased during the development of flower bud.In stageⅢ,the soluble protein content of unfruiting L.indica was 22%lower than that of fruiting L.indica.The content of free proline of unfruiting L.indica was higher than that of fruiting L.indica in stageⅠ.Except stageⅢ,the activity of superoxide dismutase(SOD)in flower buds at other stages were higher than that at seed setting.The catalase(CAT)activity of unfruiting was significantly lower than that of fruiting at the same stage of flower bud development,while the peroxidase(POD)activity of unfruiting and fruiting showed an opposite trend.At the later stage of flower bud development,the content of malondialdehyde(MDA)in fruiting was low,while the content of malondialdehyde in unfruiting was significantly increased,and the content of nutrient elements in fruiting and unfruiting flower bud was significantly different.【Conclusion】Fruiting L.indica has larger transverse and longitudinal diameter than unfruiting L.indica at the same time.The fruiting L.indica had begun to grow petals and filaments in stageⅢ,while unfruiting L.indica had no obvious petals.The contents of soluble sugar and soluble protein in flower buds of unfruiting L.indica were lower than those of fruiting L.indica of the same period.The deficiency of carbohydrate may lead to the decrease of microspore fertility and male sterility of crape myrtle flower.The unfruiting has less accumulation of free proline during flower bud development.CAT metabolism of unfruiting L.indica is not vigorous,and persistent accumulation of malondialdehyde may be a cause of unfruiting and abortive fertility.In the process of unfruiting flower bud development,the related enzyme activities may be affected due to the insufficient content of various nutrient elements,and the development of anthers will be significantly affected.