中图分类号：S725.5 文献标志码：A

Abstract： 【Objective】 Camellia oleifera is a plant of Camellia genus in Theaceae family， which is rich in nutrients and has a wide range ofutilization，and is a very important woody oil tree species.The problems offalling flowers and fruits，as well as low yield，are the key factors restricting the high-yield and eficient development of C .oleifera industry. This study aimed to investigate the effects of different phosphorous and potassium fertilization treatments done at the fruit expanding stage on the fruit and flower bud growth and development of C .oleifera，in order to a provide reference for scientific fertilization to improve C. oleifera yield.【Method】 The C oleifera variety Cenruan 3 was selected as the experimental plant material in this study. Different phosphorus and potassium fertilization amount treatments were set and applied at the fruit enlargement stage.No fertilization treatment was used as the control. Four levels of KH₂PO₄ （purity 99% ，containing P₂O₅ 52% and K₂O 34% ）treatments included A1， 250g/plant ； A2， 500g/plant ; A3， 750g/plant ； and A4， 1000g/plant ，and 4 levels of commercial phosphate fertilizer（available P₂O₅⩾16% ） + potassium fertilizer （ K₂O⩾52% ）treatments included B1， 125g/ plantof phosphate fertilizer+125 g/plant of potassium fertilizer；B2， 250g/Ω plant of phosphate fertilizer +250g/ plant of potassium fertilizer; B3， 375g/ plantof phosphate fertilizer +375g/ plant of potassium fertilizer；and B4， 500g/Ω plant of phosphate fertilizer + 500g/Ω plantof potassium fertilizer.The agronomic traits including the number of fruits，transverse and longitudinal diameter，and single fruit mass were investigated before fertilization and after fruit ripening，and the fruit retention rate and fruit shape index were calculated. 【Result】The results indicated that in terms of the effect on fruit retention rate，the treatment B4 was thebest，whichfruit retentionratereached 60.15% andwas 152.73% higher than that in the control， and it could also enhance the fruit transverse and longitudinal diameter. Regarding the effects on fruit economic traits，treatment A4 could better promote fruit growth and quality，which showed significantly higher single fruit mass and fruit shape index compared to the control；the fresh and dry seed yields，and dry kernel yield in treatment B1 were all higher than those in the control. In terms of the effects on flower bud plumpness，the treatment A2 （ KH₂PO₄500g ）presented the most favorable results，the length，width，thickness，mass，and volume of flower buds were 14.56mm ， 7.71mm ， 7.27mm ， 4.35g ，and 2.17mm³ ，respectively，which were 10.64% ， 0.78% ， 12.71% ， 11.25% ，and 1.88% ， respectively， higher than those in the control. 【Conclusion】Appropriate application of phosphorus and potassum fertilizers at the fruit expanding stage significantly improved the fruit retention rate，economic traits and plumpness of flower buds in C .oleifera.Overall， the treatment B4 （ 500g/ plant of phosphate fertilizer +500g/ plant of potassium fertilizer） had the best effect.

Keywords： Camellia oleifera； fruit retention rate； fruit economic traits；plumpness of flowerbuds

0 引言

【研究意义】油茶（Camelliaoleifera）是山茶科山茶属小乔木或灌木状植物，与油橄榄、油棕、椰子并称为世界四大木本油料树种（彭邵锋等，2012），有“东方橄榄油”的美称（庄瑞林，

2008），具有丰富的营养元素和广泛的用途，主要生长在中国南方亚热带地区的高山及丘陵地带。油茶果实生长根据其发育特点大致分为以下4个重要生长时期：幼果形成期（3月以前）、果实生长期（3一8月）、油脂转化期（8月下旬一10月）和果熟期（陈永忠等，2006；庄瑞林，2008）。近年来，油茶产业发展迅速，在我国生态经济建设中占有重要地位，但生产中存在落花落果、产量低等问题，是制约油茶产业高产高效发展的关键因素（黄安香等，2023）。广西作为全国油茶主产区之一，采取有效手段提高油茶产量对油茶产业发展具有重要意义。【前人研究进展】油茶是一种重要的经济作物，其生长发育与营养物质供应密切相关，施肥不仅能促进其花芽分化与生长，还能促进其果实的发育与形成，进而提高其产量与抗逆性（曹永庆等，2012）。有研究表明，油茶林地施用五氧化二磷（ P₂O₅ ）可获得较好的产量（ZHANGetal.，2021）。郑顓（2020）研究发现，喷施 0.3%～0.5% 的硼肥有利于提高油茶的坐果率，增加产量。姜佳艳等（2022）发现，氮肥对油茶株高、南北冠幅、单果质量影响较大，钾肥对地径增长、结果数量、单果质量及出仁率影响较大；有机肥对东西冠幅、施肥当年油茶产量、茶籽质量、茶籽含水率及含油率影响较大；磷肥对油茶产量和结果数量影响较大。【本研究切入点】前人的研究虽然为油茶施肥管理提供了理论基础，但大多集中在油茶整个生长发育期的施肥管理，针对油茶膨果期施肥研究相对较少。……