| 摘要: |
| 【目的】研究大花黄牡丹二次枝生长对结果率和结实率的影响，以及败育胚珠的发生时期和胚珠败育的生理机制，为大花黄牡丹日后的引种栽培及人工调控结实提供参考。【方法】以河南省洛阳市栾川县引种栽培的大花黄牡丹为试验材料，于2019-2021年连续3年在花果期进行二次枝发育与果实发育的田间控制试验，按照花蕾和二次枝处理的不同，分为A、B处理组和对照，其中A组保留不同花蕾，去除所有二次枝；B组保留所有二次枝，去除不同花蕾；对照组保留所有花蕾和二次枝，统计各处理的结果率和结实率；在花后12~50 d定期采集胚珠，对比分析正常胚珠与败育胚珠不同时期的生理生化指标（可溶性糖、淀粉、可溶性蛋白含量以及超氧化物歧化酶（SOD）活性）和内源激素（生长素（IAA）、赤霉素（GA3）、玉米素核苷（ZR）含量以及脱落酸（ABA））差异。【结果】1）花后10~30 d是大花黄牡丹果实的生长高峰期，也是胚珠败育主要发生时段；花后13 d正常胚珠与败育胚珠外部形态差异明显。2）A组中，保留所有花蕾的植株结实率均较高，且高于对照组；B组中，多数去除花蕾处理组结实率高于对照组，其中仅保留最下方侧花处理结实率最低。3）花后13~14 d，大花黄牡丹正常胚珠中可溶性糖含量升高，同时期的败育胚珠中可溶性糖含量降低；花后12~13 d，败育胚珠中淀粉含量最低，之后持续上升，而正常胚珠花后14 d时淀粉含量最高，之后迅速下降；花后13 d，败育胚珠可溶性蛋白含量最低，正常胚珠可溶性蛋白含量最高，花后13~15 d，败育胚珠的可溶性蛋白含量先升高后降低，正常胚珠的变化趋势与之相反；花后13~50 d，大花黄牡丹正常胚珠和败育胚珠的SOD活性总体呈上升趋势，且正常胚珠的SOD活性始终高于败育胚珠。4）花后13~20 d，大花黄正常胚珠中的IAA、GA3、ZR含量，以及（GA3+IAA+ZR）/ABA、GA3/ABA和IAA/ABA均明显高于败育胚珠，ABA含量和ABA/（GA3+IAA）低于败育胚珠。【结论】大花黄牡丹二次枝、侧花与顶花之间的竞争会导致胚珠败育，适当摘除二次枝或侧花可提高结实率；可溶性糖、淀粉、可溶性蛋白含量及SOD活性低是导致胚珠败育的生理原因；此外，胚珠败育也与胚珠内源激素异常有关。 |
| 关键词: 大花黄牡丹 结实率 胚珠败育 二次枝 营养物质 内源激素 |
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| 基金项目:国家林草局行业标准项目“牡丹综合体”(2018-LY-054）；北京市教委“双一流建设”专项北京林业大学建设世界一流学科和特色发展引导专项资金资助项目“园林植物高效繁殖与栽培技术研究”（2019XKJS0324）；西藏自治区科研院所社会公益研究专项“藏东南特有林木资源的评价与共享技术研究”（2004DIB3J097） |
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| Effect of secondary branches on seed setting rate and physiological mechanism of ovule abortion in Paeonia ludlowii |
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CHEN Tingqiao,YUAN Tao,QIAO Hongyong,et al
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| Abstract: |
| 【Objective】The effect of secondary branches growth on fruiting rate and seed setting rate of Paeonia ludlowii as well as the occurrence and physiological mechanism of ovule abortion were studied to provide reference for the introduction,cultivation and artificial regulation of seed setting of P.ludlowii.【Method】P.ludlowii plants introduced and cultivated in Luanchuan County,Luoyang,Henan were selected,and the secondary branches and fruits development field control experiments were carried out at the flowering and fruiting stages for 3 years from 2019 to 2021.According to different treatments of flower buds and secondary branches,they were divided into treatment groups of A,B and control.Treatment group A retained different flower buds and removed all secondary branches,treatment group B retained all secondary branches and removed different flower buds,and the control group retained all flower buds and secondary branches.Fruit setting rate and the seed setting rate were counted.In addition,ovules were collected regularly from 12 to 50 days after flowering,and the differences in physiological and biochemical indexes (soluble sugar,starch,soluble protein and SOD activity) and endogenous hormones (IAA,GA3,ZR and ABA) between normal ovules and aborted ovules were compared and analyzed.【Result】1) The fruit growth peak and the main period of ovule abortion was 10-30 d after flowering.It was on 13 d after flowering when the external morphology differed between normal and aborted ovules.2) Plants that removed all secondary branches before flowers opening had the highest seed setting rate.When the secondary branches were retained,the seed setting rates of the flower bud removal treatment groups were higher than those of the control group.The seed setting rate was the lowest when all secondary branches were retained and only the lowermost side flowers were retained.3) The content of soluble sugar in normal ovules increased 13 to 14 days after flowering,while that in abortive ovules decreased.From 12 to 13 days after flowering,the starch content of aborted ovules decreased and then increased continuously,while the starch content of normal ovules reached the highest value 14 days after flowering before decreasing rapidly.The soluble protein content of abortive ovules obtained the lowest and that of normal ovules reached the highest at 13 days after flowering.From 13 to 15 days after flowering,the soluble protein content of abortive ovules increased firstly and then decreased,while that of normal ovules changed oppositely.From 13 to 50 days after flowering,SOD activity of normal ovules and abortive ovules increased,and normal ovules always had higher values.4) From 13 to 20 days after flowering,the contents of IAA,GA3 and ZR and the ratios of (GA3+IAA+ZR)/ABA,GA3/ABA and IAA /ABA in normal ovules were significantly higher than those in aborted ovules,while the content of ABA and the ratio of ABA/(GA3+IAA) were lower than those in aborted ovules.【Conclusion】The competition among secondary branches,lateral and top flowers led to ovule abortion of P. ludlowii.Removing parts of secondary branches or lateral flowers could increase the seed setting rate.The low contents of soluble sugar,starch and soluble protein and SOD activity were the physiological causes of ovule abortion.Ovule abortion was also related to abnormal endogenous hormones of ovules. |
| Key words: Paeonia ludlowii seed setting rate ovule abortion secondary branch nutrients endogenous hormones |
