油茶果实生长发育动态和木质素积累规律

Fruit Development Dynamics and Lignin Accumulation Law of Oil Tea

【目的】研究6种不同油茶材料果实生长发育动态和木质素积累规律变化,鉴定油茶果实发育期,明确不同类型油茶果实形态差异形成过程以及木质素对油茶果实发育的影响。【方法】以小果油茶(Camellia meiocarpa)、攸县油茶(Camellia yuhsienensis)、普通油茶(Camellia oleifera)长林53号和长林166号、浙江红花油茶(Camellia chekiangoleosa)和茶梨油茶(Camellia octopetala)6种不同油茶材料为研究对象,对成熟油茶果实性状、果实生长发育动态以及木质素积累规律进行观测,结合观测结果对油茶果实发育时期进行了鉴定。【结果】不同类型油茶果实形态和质量相关指标均存在显著性差异,油茶果实鲜果含仁率从大到小依次为攸县油茶(19.72%)、普通油茶长林53号(16.99%)、小果油茶(14.85%)、普通油茶长林166号(12.32%)、浙江红花油茶(6.22%)和茶梨油茶(3.32%)。油茶果实发育都经历了类似S型的3个阶段:前期果实大小和质量变化缓慢,中期发育较快,后期逐渐平稳。浙江红花油茶和攸县油茶分别是果实成熟时期最早和最晚的油茶类型。小果油茶、普通茶油和茶梨油茶果实发育周期基本一致。不同类型油茶果实不同生长发育阶段的持续时间、形态和质量变化规律具有各自特点。油茶果皮发育经历了“增厚-延展”的过程,不同类型油茶果皮增厚与延展的起始时间、终止时间和持续时间存在一定差异,油茶果皮延展的时期与果实生长发育迅速的时间吻合。果皮发育以果皮完全木质化的时期作为分界线,可以分为增厚期和延展期。种子发育分别以种子填充种皮空间、种仁成型和种皮完全木质素化为分界线,分为发育前期、种仁形成期和种子膨大期3个时期。油茶果实果皮和种皮组织(种壳)都具有木质素积累,除浙江红花油茶外,其余5种类型油茶果皮中木质素积累的方式都是从外向内,呈射线状,逐渐充满整个果皮组织中。【结论】果皮发育的差异是导致不同类型油茶果实形态差异的主要原因,油茶果皮木质化过程影响了果实发育,木质素积累越早,果皮厚度越薄,果实越小。种子的最终形态与种皮中的木质素积累情况具有直接关系。

[Objective]To understand the fruit formation of different types of oil tea materials,the dynamic changes in fruit development and lignin accumulation of six oil tea germplasms were studied.[Method]The mature fruit characteristics,dynamics of fruit growth and development and lignin accumulation patterns of Camellia meiocarpa,Camellia yuhsienensis,Camellia oleifera‘Changlin 53’,Camellia oleifera‘Changlin 166’,Camellia chekiangoleosa and Camellia octopetala were measured and compared,and the fruit development period was identified.[Result]It was found that there were significant differences in fruit morphology and weight-related characteristics of oil tea germplasms;and the kernel ratios were listed as follows:C.yuhsienensis(19.72%),C.oleifera‘Changlin 53’(16.99%),C.meiocarpa(14.85%),C.oleifera‘Changlin 166’(12.32%),C.chekiangoleosa(6.22%)and C.yuhsienensis(3.32%).The fruit development of oil tea materials had a similar S-shaped trend:the fruit size and weight displayed slow increases at the early stage,rapid expansionat at the middle stage,and kept a steady state at the late stage.C.chekiangoleosa and C.yuhsienensis were the earliest and latest types of fruit ripening,respectively.The fruit developmental cycles of C.meiocarpa,C.oleifera and C.octopetala were similar in general.The duration of different developmental stages and the morphological characteristics of oil tea types were different.The pericarp development was characterized as an“Expansion-Extension”process,and there were some differences in the time of initiation,termination and duration of the processes.The phase of pericarp“Expansion”coincided with the time of rapid seed development of oil tea.The pericarp and seed coat(seed shell)of oil tea had high levels of lignin,except for C.chekiangoleosa,in which the fruits were lignified from outside to inside,gradually filling the entire pericarp.The lignification of pericarp was the dividing line of“Expansion-Extension”process.Seed development was divided into 3 periods,including pre-developmen(t until seed-filling),seed formation(until seed kernel molding)and seed expansion(until complete lignification of seed coat).[Conclusion]The difference in the development of the pericarp was the main cause of the changes in fruit size in oil tea.It was found that the sooner the lignification begins,the thinner the pericarp is during the fruit development of oil tea.The final production of the seeds of oil tea is also directly related to the lignification of seed coat of oil tea.