对 18 个芳樟[Cinnamomum camphora (L.) Presl]无性系叶片光合色素含量和叶绿素荧光参数进行了测定,并对各参数的相关性进行了分析;基于上述测定结果对供试的 18 个芳樟无性系进行了聚类分析。 结果表明:芳樟不同无性系叶片叶绿素 a、叶绿素 b 及类胡萝卜素含量分别为 0. 60 ~ 2. 26、0. 24 ~ 1. 15 和 0. 14 ~ 0. 50 mg· g^-1 ,差异较大,部分无性系间叶绿素 a 和 b 以及类胡萝卜素含量差异达显著水平;其中,无性系 BT2 叶片的叶绿素 a 含量在18 个无性系中最高,叶绿素 b 及类胡萝卜素的含量也较高。 各无性系间叶片的初始荧光( F₀ )、PSⅡ最大光化学效率(F_v / F_m)、PSⅡ潜在活性(F_v / F₀ )、PSⅡ电子传递情况(F_m / F₀ )、光化学淬灭系数(Q_p)、非光化学淬灭系数( NPQ)和 PSⅡ实际光化学效率(Q_y)差异明显,且部分无性系间的差异达显著水平;各无性系间的最大荧光( F_m )、可变荧光(F_v)和荧光下降比值(Rfd)差异不显著。 在各叶绿素荧光参数中,F₀ 与 F_m显著正相关;F_m与 F_v、F_v / F_m、F_v / F₀ 、F_m / F₀以及 F_v / F_m与 F_v、 F_v / F₀ 、 F_m / F₀ 、 Q_y间均存在极显著正相关,其中 F_v / F_m与 F_v / F₀ 、 F_m / F₀的相关系数均达0. 98;Q_p与 NPQ、Rfd呈极显著正相关,与其他参数则总体上呈负相关;Q_y与 F_m、F_v、F_v / F_m、F_v / F₀ 、F_m / F₀ 以及 Rfd与NPQ、Q_p、Q_y均存在显著或极显著正相关。 采用欧氏距离法,可将 18 个无性系划分为 2 类:第 1 类包含 16 个无性系;第 2 类仅包含无性系 PC5 和 WP1。 第 1 类又可进一步划分为 2 个亚类:第 1 亚类仅包含无性系 BY2;第 2 亚类共包含 15 个无性系,其中的 BT1 与 BT2 距离最短,光合生理特征最接近。 根据研究结果,初步推断芳樟各无性系叶片的潜在光化学活性和电子传递情况共同影响 PSⅡ光能转换效率;无性系 116、187、BT1 和 MD1 对光能的利用率较高;无性系 BT2 则具有良好的光合生理性能。

 

Photosynthetic pigment content and chlorophyll fluorescence parameter in leaves of eighteen clones of Cinnamomum camphora ( L.) Presl were determined and their correlation was also analyzed. And cluster analysis of eighteen clones was carried out based on above determination results. The results show that contents of Chla, Chlb and carotenoid in leaves of different clones are respectively 0. 60-2. 26, 0. 24-1. 15 and 0. 14 -0. 50 mg· g^-1 with greater difference, and the difference among some clones is significant. In which, Chla content of clone BT2 is the highest and its Chlb and carotenoid contents are also higher among all clones. Differences of initial fluorescence (F₀), maximal photochemical efficiency of PSⅡ ( F_v / F_m ), potential activity of PS Ⅱ ( F_v / F₀ ), electronic transfer case of PS Ⅱ ( F_m / F₀ ), photochemical quenching coefficient (Qp), non-photochemical quenching coefficient (NPQ) and actual photochemical efficiency of PSⅡ (Q_y) among all clones are obvious, and those among some clones are significant. Differences of maximal fluorescence (F_m), variable fluorescence (F_v) and fluorescence decrease ratio ( Rfd ) are not significant among all clones. Among all of chlorophyll fluorescence parameters, F0 has a significantly positive correlation with Fm. Positive correlations between Fm with F_v, F_v/ F_m, F_v / F₀, F_m / F₀ and between F_v / F_m with Fv, F_v / F₀, F_m / F₀, Q_y are extremely significant, in which the correlation coefficients between Fv/ Fm with Fv / F0 and Fm / F₀ both are 0. 98. There is extremely significant positive correlation between Q_p with NPQ and Rfd, but the correlation between Q_p with others parameters is generally negative. The positive correlations between Q_y with F_m, F_v, F_v / F_m, F_v/ F₀, F_m / F₀ and between Rfd with NPQ, Q_p, Q_y are significant or extremely significant. By  euclidean  distance method, eighteen clones are divided into two classes: the first class contains sixteen clones and the second class only contains clones PC5 and WP1. And the first class can be further divided into two sub-classes: the first sub-class only contains clone BY2, the second sub-class contains fifteen clones in which distance of clones BT1 and BT2 is the closest with the most similar photosynthetic physiological characteristics. According to these results, it is preliminarily inferred that potential photochemical activity and electronic transfer case of leaves of C. camphora clones commonly affect on light energy conversion efficiency of PSⅡ and clones 116, 187, BT1 and MD1 have the better characters to use light energy. In addition, clone BT2 possesses the better photosynthesis characters.