以九龙袍品种为研究对象,测定不同叶位(1～6叶)的光合参数、叶绿素含量、鲜叶生化成分等差异,旨在明确九龙袍品种的光合特性与品质成分.结果表明:净光合速率、蒸腾速率随叶片成熟度的增加而下降；胞间CO2浓度随叶位变化规律不明显；叶绿素a、叶绿素b以及叶绿素总量从嫩叶到成熟叶片含量逐渐增加;RuBP羧化酶、POD酶活力从嫩叶到成熟叶逐渐增强,到第6叶最强,分别是46.42 μmol·m-2·s-1(最终活力)和34.21 μmol·m-2·s-1.CAT酶活力则表现为第2、3叶较低,之后随叶片成熟逐渐增强.与品质成分相关的水浸出物含量、茶多酚总量、氨基酸含量、咖啡碱含量均表现不同的变化规律:水浸出物含量第2叶最高,达到44.28％,从第3叶开始逐渐下降；茶多酚含量第1、2叶位较高(均大于20％),到第3叶开始随着鲜叶嫩度的降低总体表现出下降的趋势；氨基酸含量第1叶最高,为4.84％,后随着叶位的增加含量有逐渐降低的趋势,第6叶含量为3.18％;各叶位咖啡碱含量变化不具有明显的规律性,含量介于2.5％与3.0％之间;纤维素的含量从第1叶到第6叶逐渐增加,从第1叶的7.99％增加到第6叶的17.30％.%Using a portable photosynthetic meter, the photosynthetic characteristics of Jiulongpao (C. Sinensis cv. Jiulongpao) tea plant were determined. Measurements were made on the leaves of the plants. Various factors concerning the tea quality were analysed. The results showed that the rates of net photosynthetic (Pn) and transpiration (Tr) decreased as the plant matured. The plant's intercellular CO2 concentration (Ci) showed no significant difference among the leaves from different positions on a plant. The contents of chlorophyll a, chlorophyll b and total chlorophy increased from the 1" leaf to the 6th leaf. So did the activities of ribulose diphosphatecarboxylase (RUBP) and peroxidase (POD) enzymes, at 46.42 μmol·m-2·s-1 and 34. 21μmol·m-2 ·s-1, respectively, on the 6th leaf. The activities of catalase (CAT) were lower in the 2nd and 3rd leaves than the others. The quality indices, such as aqueous extract, tea polyphenols, amino acids and caffeine in Jiulongpao, varied in different leaves. The water extract of the 2nd leveas was the highest (44. 28%) among all. The polyphenols contents in the 1" and 2nd leaf were higher than the others. The amino acid content in the 1" leaf was 4. 84%, which was significantly higher than the others. It decreased with maturity of the leaves. The caffeine contents in all leaves were between 2. 5% and 3%. The cellulose increased from the 1" leaf (7. 99%) to the 6th (17. 3%).
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