Effects of Partial Leaf Area Reduction on Yield and Quality of Camellia oleifera | 不同叶面积损失对油茶产量及品质的影响

Chinese. 2011年5月对12年生、树高1.5～2.1m、造林密度为1500株・hm-2的普通油茶进行不同面积剪叶处理,以此模拟病虫等的危害,研究油茶叶片损失对其产量和品质的影响。结果表明：不同剪叶处理对油茶落果率、果实质量、果实鲜出籽率、出仁率、干仁含油率均有一定影响。当叶损失量（剪叶量）为25%,50%和75%时,落果率分别为61.2%,83.8%和84.1%,是对照的1.54,2.11和2.12倍,显著高于对照;而叶损失量为12.5%时,油茶落果率与对照差异不显著。当叶损失量高于25%时,鲜出籽率（低于41%）、出仁率（低于14%）和干仁含油率（低于37%）均出现明显的下降趋势,与对照（44.6%,14.7%和42.2%）差异显著;瘪籽率则随着剪叶量的增加而上升。剪叶对茶油中饱和脂肪酸――棕榈酸和不饱和脂肪酸――油酸的含量也有影响,尤其是剪叶75%后,茶油中棕榈酸的含量为24.8%,比对照的（9.2%）显著增高;油酸的含量为68.9%,比对照的（82.5%）显著降低。剪叶后对油茶植株翌年（2012年）的生长及结果情况调查表明：剪叶50%和75%的树势衰弱,抽梢不正常且新叶少,平均果实数仅为2.2和0个・株-1,基本没有结果,显著低于其他处理组;而剪叶12.5%的油茶树翌年生长正常,结果数与对照差异不显著。研究结果表明叶面积损失超过25%将严重影响油茶的产量和翌年树势的生长,叶面积损失12.5%以上对茶油的品质有一定影响。

English. Camellia oleifera is an endemic woody oily tree species in China. It is one of economic forest tree species with the largest cultivation area and widest distribution. In May 2011, leaves of 12-year-old C. oleifera were trimmed with different area to simulate leaf loss caused by disease and insect pests, when the height of the trees was 1.5-2.1 m, and the stand density was 1 500 trees per hm2. The effect of partial leaf area reduction on the yield and quality of C. oleifera was evaluated. Results showed that the leaf trimming had impact on fruit abscission ratio, average fruit weight, fresh kernel ratio, kernel yield ratio and oil yield ratio of dry kernel. The fruit abscission ratio were 61.2%, 83.8% and 84.1% respectively, when the leaf trimming were 25%, 50% and 75%, which was 1.54, 2.11, and 2.12 times higher than the control. There was no significant difference in fruit abscission ratio between 12.5% leaf trimming and the control. When the leaf trimming was over 25%, fresh kernel ratio was less than 41%, kernel yield ratio less than 14% and oil yield ratio less than 37%, in compared with the control （44.6%, 14.7% and 42.2%, respectively）. All the parameters had a decline trend with the trimming. But the shriveled kernel ratio showed a contrary trend, which was increased with increasing the trimmed leaf area. The leaf trimming also had effect on the contents of palmitic acid and oleic acid of the tea oil. Leaf trimming by 75% significantly increased the content of palmitic acid （saturated fatty acid） and decreased the content of oleic acid （unsaturated fatty acid）. When the leaf area was trimmed by 50% and 75%, the vigor of C. oleifera trees weakened, sprout was abnormal, new leaves became less, and the average number of fruits was only 2.2 and 0 per tree, respectively which was significantly lower than other treatments. When the leaf area was trimmed by 12.5%, C. oleifera trees had normal growth in the next year and the number of fruits had no difference with the control. The results showed that when defoliation was over 25%, the yield and vigor of the trees in the second year would be affected, and when defoliation above 12.5%, the quality of tea oil would be affected.