植物叶片特征与光合性能的关系

Relational analysis of leaf characteristics and photosynthetic capacities of plants

  • 摘要: 以相同生境下生长的5种叶片特征(叶色和厚薄等)不同的植物珊瑚树(Viburnum odoratissimum)、银杏(Ginkgo Biloba)、桑树(Morus alba)、紫叶酢浆草(Oxalis triangularis cv. Purpurea)和紫叶橡皮树(Ficus elastica cv. Decora Burgundyi)为材料, 于晴天选择其植株上东南朝向且生长一致并具代表性的当年生成长叶, 采用Li-Cor 6400便携式光合测定系统、调制叶绿素荧光成像系统(IMAGING-PAM M-Series)及双通道PAM-100测量系统(Dual-PAM-100)和常规方法研究了其叶片特征、光合性能及相互间的关系。结果表明, 不同植物的叶片特征和光合性能指标均存在显著或极显著差异。比叶干重35~215 g(DW)·m-2间的差异大于比叶鲜重0.28~1.04 kg(FW)·m-2。桑树和珊瑚树叶的叶绿体色素含量叶绿素a (Chla)、叶绿素b (Chlb)、叶绿素总量(Chl)和类胡萝卜素(Xc)较高, 银杏叶和紫叶橡皮树叶居中, 紫叶酢浆草叶最低; 紫叶酢浆草叶的花青素(Ant)含量最高0.122 mg·g-1(FW)和0.488 mg·g-1(DW), 其他植物较低且差异较小; 紫叶酢浆草叶的Chla/Chlb(6.27)、桑树的Chl/Xc(9.97)、桑树叶的Chl/Ant(43.81)和珊瑚树叶的Xc/Ant(7.17)最高, 紫叶酢浆草叶的Chl/Ant(0.49)和Xc/Ant(2.46)最低。气孔导度、蒸腾速率、胞间CO2浓度和净光合速率(Pn)均为桑树>银杏>紫叶酢浆草>珊瑚树>紫叶橡皮树。桑树和珊瑚树叶的PSII实际光合效率Y(II)最高, 但PS II处非调节性能量耗散的量子产量也最高; 银杏Y(II)叶较低, 但能抵御强光的照射。桑树、紫色酢浆草和紫色橡皮树叶的PSI光合效率Y(I)极高, 但桑树和紫色橡皮树PSI的光保护较弱, 紫色酢浆草则很强。相关分析显示, Ant和Xc对强光下Pn无显著影响, Pn受气孔特征和叶绿素含量的正调控, Y(II)依赖于叶绿体色素含量(尤其是Chla), Y(I)与Chl/Xc呈正向关系; 气孔开放和叶绿素含量可负调控光合机构的光保护和正调控光损伤, Xc则相反。

     

    Abstract: Southeast-facing matured leaves of five plants Viburnum odoratissimum (VO), Ginkgo biloba (GB), Oxalis triangularis cv Purpurea (OTP), Ficus elastica cv. Decora Burgundyi (FEDB) and Morus alba (MA) were used to determine the characteristics and photosynthetic capacities of plant leaves in sunny days. The Li-Cor 6400 Portable Photosynthesis Measuring System, Modulated Chlorophyll Fluorescence System (IMAGING-PAM M-Series), Dual-PAM-100 Measuring System and conventional methods were used to analyze the relationships among leaf characteristics and photosynthetic capacities. The results showed significant differences (P < 0.05 or P < 0.01) in leaf characteristics and photosynthetic capacities among different plants. Differences in specific leaf dry weight 35~215 g (DW)·m-2 among plants were higher than those in specific leaf fresh weight 0.28~1.04 kg (FW)·m-2. Leaf chloroplast pigment contents chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (Chl) and carotenoid (Xc) of MA and VO were the highest, followed by GB and FEDB and those of OTP were the lowest. While anthocyanin (Ant) content of OTP was maximum for 0.122 mg·g-1(FW) and 0.488 mg·g-1(DW), those of the others plants were low and similar. While OTP leaf Chla/Chlb (6.27), MA leaf Chl/Xc (9.97), MA leaf Chl/Ant (43.81) and VO leaf Xc/Ant (7.17) were the highest, OTP leaf Chl/Ant (0.49) and Xc/Ant (2.46) were the lowest. The orders of stomata conduction, transpiration rate, intercellular CO2 concentration and net photosynthetic rate (Pn) of the plants were MA > GB > OTP > VO > FEDB. MA and VO leaf practical quantum PSII Y(II) was the highest and that of GB was low. Although MA, OTP and FEDB PSI were high, MA and FEDB PSI photo-protection was weak and that of OTP strong. Correlation analysis indicated that the effects of Ant and Xc on Pn were insignificant. Also stomata characteristics and chlorophyll content positively regulated P>/i>n. Y(II) mainly depended on chloroplast pigment content (especially Chla) and the relationship between Y(I) and Chl/Xc was positive. Leaf stomata opening and chlorophyll content negatively regulated PSII and PSI photo-protection. It, however, positively regulated PSII photo-damage. The effect of Xc was the exact reverse of that of Chl.