文冠果落果差异的营养−激素调控机制与 SSR 遗传分析

Regulatory mechanisms of nutrition-hormone underlying fruit drop differences and SSR genetic analysis of Xanthoceras sorbifolium

摘要

【目的】为明确文冠果落果的生理调控机制与种质遗传特性，本研究探究无性系落果率与营养、内源激素的关联规律，筛选低落果率优良无性系，分析种质遗传多样性，以期为文冠果种质创新及高产育种提供依据。【方法】以 22 个文冠果无性系为试验材料，在第 1 次落果高峰开展落果率和新梢生长量观测、叶片与果实碳水化合物和内源激素测定，分析各指标与落果率的相关性及积累规律；为进一步解析 22 份无性系不同表型内在的遗传基础，采用 20 对 SSR 引物对不同种质开展遗传多样性分析。【结果】（1）22 个无性系落果率 39.54% ~ 81.02%，可划分为低、中、高落果率 3 类，筛选出 121、171、102 等低落果率无性系，且落果率与新梢生长量呈极显著正相关，表明梢果养分竞争是诱发幼果脱落的重要原因。（2）在碳水化合物方面，可溶性糖在叶、果中呈现正常果 > 叶片 > 脱落果，淀粉则呈现叶片 > 正常果 > 脱落果的积累规律，低落果率无性系果实中可溶性糖、淀粉含量显著高于高落果率无性系，其光合产物向果实转运效率更高。（3）低落果率无性系正常果和脱落果中 IAA、GA₃、ZT 含量显著高于高落果率无性系，而 ABA、JA 含量显著低于高落果率无性系，表明不同无性系间激素平衡状态差异是造成落果差异的重要内在生理基础。（4）20 对 SSR 引物平均 PIC 为 0.60，种质遗传多样性丰富，为低落果优良无性系筛选提供了良好遗传基础；但落果率表型聚类与 SSR 分子聚类匹配度较低，原因可能在于落果属于数量性状，且易受环境调控。【结论】本研究筛选出 121、171、102 等低落果率无性系，养分分配与内源激素平衡是调控文冠果无性系落果水平的关键生理基础，且 22 份文冠果种质资源的遗传多样性丰富，育种潜力优良。本研究从生理特征与遗传背景两个维度初步解析了落果差异的调控机制，研究结果为文冠果良种筛选与栽培调控提供了理论支撑。

Abstract

[Objective] To clarify the physiological regulation mechanism of fruit drop and germplasm genetic characteristics ofXanthoceras sorbifolium, this study explored the correlation between fruit drop rate and nutrients as well as endogenous hormones, screened excellent clones with low fruit drop rate, and analyzed germplasm genetic diversity, so as to provide a basis for germplasm innovation and high-yield breeding of X. sorbifolium. [Method] A total of 22X. sorbifolium clones were used as experimental materials. Observations on fruit drop rate and new shoot growth, and determinations of carbohydrate and endogenous hormone contents in leaves and fruits were conducted during the first fruit drop peak. The correlation and accumulation patterns between each index and fruit drop rate were analyzed. To resolve the intrinsic genetic basis of phenotypic differences among the 22 clones, 20 pairs of SSR primers were adopted to analyze the genetic diversity of tested germplasms. [Result] (1) The fruit drop rate of the 22 clones ranged from 39.54% to 81.02%, which could be classified into three groups: low, moderate and high fruit drop rate. Clones 121, 171 and 102 with low fruit drop rate were screened out. The fruit drop rate was extremely significantly positively correlated with new shoot growth, revealing that nutrient competition between shoots and fruits is an important cause of young fruit abscission. (2) For carbohydrates, soluble sugar content followed the order of normal fruit > leaf > abscised fruit, and starch content followed leaf > normal fruit > abscised fruit. The contents of soluble sugar and starch in fruits of low fruit-drop clones were significantly higher than those of high fruit-drop clones, demonstrating higher translocation efficiency of photosynthates to fruits. (3) The contents of IAA, GA₃ and ZT in normal and abscised fruits of low fruit-drop clones were significantly higher than those of high fruit-drop clones, while ABA and JA contents were significantly lower. This indicates that differences in hormone balance among clones constitute an important intrinsic physiological basis for fruit drop differentiation. (4) The average PIC value of the 20 pairs of SSR primers was 0.60, and the tested germplasms possessed abundant genetic diversity, which provides a favorable genetic foundation for screening low fruit-drop elite clones. Nevertheless, the matching degree between fruit drop phenotypic clustering and SSR molecular clustering was low, because fruit drop is a quantitative trait susceptible to environmental regulation. [Conclusion] Clones 121, 171 and 102 with low fruit drop rate were identified in this study. Nutrient allocation and endogenous hormone balance act as the key physiological basis regulating the fruit drop level ofX. sorbifolium clones. The 22 tested germplasms have rich genetic diversity and excellent breeding potential. This study preliminarily elucidated the regulatory mechanisms underlying differences in fruit drop from the two dimensions of physiological traits and genetic background, providing theoretical support for the selection of superior varieties and cultivation management of X. sorbifolium.

关键词

文冠果 / 落果 / SSR 标记 / 碳水化合物 / 激素 / 遗传多样性 / 种质筛选

Key words

Xanthoceras sorbifolium / fruit drop / SSR markers / carbohydrates / hormones / genetic diversity / germplasm screening

参考文献

[1] Yuan C J, Yan R, Wang B X, et al. The importance of yellowhorn (Xanthoceras sorbifolia) for restoration of arid habitats and production of bioactive seed oils [J].Ecological Engineering, 2017, 99: 504-512.

[2] Zang E, Qiu B, Chen N, et al. Xanthoceras sorbifolium Bunge: a review on botany, phytochemistry, pharmacology, and applications [J].Frontiers in Pharmacology, 2021, 12: 708549.

[3] 廖志鹏, 邹中华, 胡冬南, 等. 环割时间和弧度对盛果期油茶树体营养分配及结实的影响 [J].江西农业大学学报, 2024, 46(5): 1244-1255.

[4] Liao Z P, Zou Z H, Hu D N, et al. Effects of ring—cutting time and arc on nutrient allocation and fruiting of Camellia oleifera trees in full—fruiting season [J].Acta Agriculturae Universitatis Jiangxiensis, 2024, 46(5): 1244-1255.

[5] Eccher G, Botton A, Dimauro M, et al. Early induction of apple fruitlet abscission is characterized by an increase of both isoprene emission and abscisic acid content [J].Plant Physiology, 2013, 161(4): 1952-1969.

[6] Iglesias D J, Tadeo F R, Primo—Millo E, et al. Carbohydrate and ethylene levels related to fruitlet drop through abscission zone A in citrus [J].Trees, 2006, 20(3): 348-355.

[7] 许培磊, 韩先焱, 李昌禹, 等. 果树落花落果机制研究进展 [J].特产研究, 2018, 40(4): 82-91.

[8] Xu P L, Han X Y, Li C Y, et al. Overview of flower and fruit drop mechanism of fruit trees [J].Special Wild Economic Animal and Plant Research, 2018, 40(4): 82-91.

[9] 黄永敬, 马培恰, 吴文, 等. 砂糖橘夏梢生长对果实糖代谢及脱落的影响 [J].园艺学报, 2013, 40(10): 1869-1876.

[10] Huang Y J, Ma P Q, Wu W, et al. Effects of summer shoot growth on sugar metabolism and abscission of fruitlet in ‘Shatangju’ mandarin [J].Acta Horticulturae Sinica, 2013, 40(10): 1869-1876.

[11] Li C, Wang Y, Huang X, et al. An improved fruit transcriptome and the identification of the candidate genes involved in fruit abscission induced by carbohydrate stress in litchi [J].Frontiers in Plant Science, 2015, 6: 439.

[12] 盛德策, 丰庆荣, 李凤兰, 等. 文冠果授粉习性和果实发育规律的研究 [J].辽宁林业科技, 2010(4): 1−4 + 58.

[13] Sheng D C, Feng Q R, Li F L, et al. Pollination characteristics and fruit development law of Xanthoceras sorbifolia [J].Journal of Liaoning Forestry Science & Technology, 2010(4): 1−4 + 58.

[14] 侯瑞丽. 文冠果落果影响因素和成因机理研究 [D].太谷：山西农业大学, 2021.

[15] Hou R L. Study on influencing factors and formation mechanism of the Xanthoceras sorbifolium Bunge fruit abscission[D]. Taigu: Shanxi Agricultural University,2021.

[16] Weyers J D B, Paterson N W. Plant hormones and the control of physiological processes [J].New Phytologist, 2001, 152(3): 375-407.

[17] Cheng X, Ruyter—Spira C, Bouwmeester H. The interaction between strigolactones and other plant hormones in the regulation of plant development [J].Frontiers in Plant Science, 2013, 4: 199.

[18] 杨波, 车玉红, 郭春苗, 等. 扁桃生理落果期不同组织激素浓度的动态变化及其对落果的影响 [J].西北植物学报, 2015, 35(1): 118-124.

[19] Yang B, Che Y H, Guo C M, et al. Dynamic change of hormone in the different tissue of almond during physiological fruit drop and its effect on fruit drop [J].Acta Botanica Boreali—Occidentalia Sinica, 2015, 35(1): 118-124.

[20] 贾晓梅, 张保石, 温陟良. 冬枣果实内源激素水平对其坐果的影响 [J].中国果树, 2010(4): 16-18.

[21] Jia X M, Zhang B S, Wen Z L. Effects of endogenous hormones levels in winter jujube (Ziziphus jujuba Mill. cv. Dongzao) fruits on fruit set [J].China Fruits, 2010(4): 16-18.

[22] 张淑文, 梁森苗, 郑锡良, 等. 杨梅果实发育过程中内源激素的变化与采前落果的关系 [J].植物生理学报, 2019, 55(8): 1267-1275.

[23] Zhang S W, Liang S M, Zheng X L, et al. The relationship between changes of endogenous hormones and pre—harvest fruit dropping of Chinese bayberry during fruit development [J].Plant Physiology Journal, 2019, 55(8): 1267-1275.

[24] 吴尚, 马履一, 段劼, 等. 文冠果花期和果期内源激素的动态变化规律 [J].西北农林科技大学学报 (自然科学版), 2017, 45(4): 111-118.

[25] Wu S, Ma L Y, Duan J, et al. Changes of endogenous hormones in Xanthoceras sorbifolium Bunge at florescence and fruit periods [J].Journal of Northwest A& F University (Natural Science Edition), 2017, 45(4): 111-118.

[26] 尹明宇, 吴波, 乌云塔娜, 等. 基于表型性状和 SSR 标记的樟子松核心种质构建 [J].中南林业科技大学学报, 2025, 45(6): 182-190.

[27] Yin M Y, Wu B, Wuyuntana, et al. Construction of a core collection of Pinus sylvestris var. mongolica based on phenotypic traits and SSR markers [J].Journal of Central South University of Forestry & Technology, 2025, 45(6): 182-190.

[28] Wang Y L, Zhu L Z, Li Y. Genetic relationships among 15 Xanthoceras sorbifolium cultivars using SSR markers and phenotypic traits [J].Journal of Animal & Plant Sciences, 2023, 33(2): 357-366.

[29] 申展. 基于形态学特性和 SSR 分子标记的文冠果种质资源评价与选优研究 [D].北京林业大学, 2017.

[30] Shen Z. Valuation and selection of Xanthoceras sorbifolium Bunge germplasm by morphology characteristics and SSR markers[D].Beijing Forestry University, 2017.

[31] 李思琪, 张文臣, 杨柳, 等. 基于 SSR 标记的文冠果遗传多样性分析及指纹图谱构建 [J].生物技术通报, 2024, 40(5): 74-83.

[32] Li S Q, Zhang W C, Yang L, et al. Genetic diversity analysis and DNA fingerprint construction based on SSR markers for Xanthoceras sorbifolia [J].Biotechnology Bulletin, 2024, 40(5): 74-83.

[33] 柴春山, 芦娟, 蔡国军, 等. 文冠果人工种群的果实发育与落花落果特性研究 [J].植物研究, 2012, 32(1): 110-114.

[34] Chai C S, Lu J, Cai G J, et al. Characteristics of fruit development and flower and fruit drops of artificial population of Xanthoceras sorbifolia [J].Bulletin of Botanical Research, 2012, 32(1): 110-114.

[35] 张燕, 郭晋平, 张芸香. 文冠果落花落果成因及保花保果技术研究进展 [J].经济林研究, 2012, 30(4): 180-184.

[36] Zhang Y, Guo J P, Zhang Y X. Advances in research on drop causes and retention techniques in Xanthoceras sorbifolia [J].Nonwood Forest Research, 2012, 30(4): 180-184.

[37] 李小方, 张志良. 植物生理学实验指导 [M]. 5 版.北京: 高等教育出版社, 2016.

[38] Li X F, Zhang Z L. Experimental Guide to Plant Physiology[M]. 5th ed. Beijing: Higher Education Press,2016.

[39] Bi Q X, Guan W B. Isolation and characterisation of polymorphic genomic SSRs markers for the endangered tree Xanthoceras sorbifolium Bunge [J].Conservation Genetics Resources, 2014, 6(4): 895-898.

[40] Lebon G, Brun O, Magné C, et al. Photosynthesis of the grapevine (Vitis vinifera) inflorescence [J].Tree Physiology, 2005, 25(5): 633-639.

[41] Hieke S, Menzel C M, Doogan V J, et al. Shoot development, chlorophyll, gas exchange and carbohydrates in lychee seedlings (Litchi chinensis) [J].Tree Physiology, 2002, 22(13): 947-953.

[42] Marcelis L F M. Effect of assimilate supply on the growth of individual cucumber fruits [J].Physiologia Plantarum, 1993, 87(3): 313-320.

[43] Trueman S J, Turnbull C G N. Fruit set, abscission and dry matter accumulation on girdled branches of macadamia [J].Annals of Botany, 1994, 74(6): 667-674.

[44] 陈隆升, 陈永忠, 许彦明, 等. 油茶花、果及春梢生长相关性研究 [J].中南林业科技大学学报, 2018, 38(1): 1−5,54.

[45] Chen L S, Chen Y Z, Xu Y M, et al. Research on correlation of flower bud, fruit and spring shoot growth of Camellia oleifera Abel [J].Journal of Central South University of Forestry & Technology, 2018, 38(1): 1−5,54.

[46] 武晓红, 赵习平, 李立颖, 等. 极早熟杏果实与新梢的生长发育动态及其相关性研究 [J].河北农业科学, 2016, 20(3): 20-23.

[47] Wu X H, Zhao X P, Li L Y, et al. Studies on growth dynamic and the correlation of very early maturing apricot fruits and twigs [J].Journal of Hebei Agricultural Sciences, 2016, 20(3): 20-23.

[48] Legros S, Mialet S I, Caliman J, et al. Phenology, growth and physiological adjustments of oil palm (Elaeis guineensis) to sink limitation induced by fruit pruning [J].Annals of Botany, 2009, 104(6): 1183-1194.

[49] Hieke S, Menzel C M, Doogan V J, et al. The relationship between fruit and leaf growth in lychee (Litchi chinensis Sonn.) [J].Journal of Horticultural Science and Biotechnology, 2002, 77(3): 320-325.

[50] 潘瑞炽, 董愚得. 植物生理学 (第三版)[M].高等教育出版社, 1995.

[51] Pan R C, Dong Y D. Plant Physiology (3rd ed.)[M]. Beijing: Higher Education Press,1995.

[52] 马崇坚, 柳俊, 谢从华. 茉莉酸类物质的功能与胁迫防御 [J].华中农业大学学报, 2001, 20(6): 603-608.

[53] Ma C J, Liu J, Xie C H. Functions of jasmonates and defense of stress [J].Journal of Huazhong Agricultural University, 2001, 20(6): 603-608.

[54] Sawicki M, Aït Barka E, Clément C, et al. Crosstalk between environmental stresses and plant metabolism during reproductive organ abscission [J].Journal of Experimental Botany, 2015, 66(7): 1707-1719.

[55] 王娅丽. 文冠果种质资源遗传多样性评价、重要表型性状全基因组关联分析及新品种选育研究 [D].兰州: 甘肃农业大学, 2022.

[56] Wang Y L. Genetic diversity evaluation, genome—wide association study for important phenotypic traits and new cultivar selection of Xanthoceras sorbifolium germplasm[D]. Lanzhou: Gansu Agricultural University,2022.

[57] 德永军, 姬媛媛, 张佳敏, 等. 内蒙古东部地区文冠果遗传多样性与亲缘关系分析 [J].内蒙古农业大学学报 (自然科学版), 2020, 41(1): 25-31.

[58] De Y J, Ji Y Y, Zhang J M, et al. Analysis of genetic diversity and phylogenetic relationship of Xanthoceras in eastern Inner Mongolia [J].Journal of Inner Mongolia Agricultural University (Natural Science Edition), 2020, 41(1): 25-31.

[59] 吴丽艳, 杜光辉, 鲍锐, 等. 茄子种质资源的农艺性状与 SSR 标记的遗传多样性研究 [J].云南大学学报 (自然科学版), 2018, 40(4): 820-828.

[60] Wu L Y, Du G H, Bao R, et al. Analysis of genetic diversity of eggplant germplasms by agronomic characters and SSR markers [J].Journal of Yunnan University (Natural Science Edition), 2018, 40(4): 820-828.

[61] 刘洪, 徐振江, 饶得花, 等. 基于形态学性状和 SSR 标记的花生品种遗传多样性分析和特异性鉴定 [J].作物学报, 2019, 45(1): 26-36.

[62] Liu H, Xu Z J, Rao D H, et al. Genetic diversity analysis and distinctness identification of peanut cultivars based on morphological traits and SSR markers [J].Acta Agronomica Sinica, 2019, 45(1): 26-36.

基金资助

国家重点研发计划(2024YFD2201101-6)

北京林业大学科技创新计划项目(2025XJ04)