Varietal Differences in the Photosynthetic Characteristics of Pennisetum purpureum, Schum

Revista Brasileira de Zootecnia

Bressan-Smith, Ricardo Enrique²  Silva, Manoel Messias Pereira da¹  Silva, José Fernando Coelho da¹  Vasquez, Hernan Maldonado¹  Erbesdobler, Eleonora D'Avila² 

[1] Universidade Estadual do Norte Fluminense, Campos dos Goytacazes;Universidade Estadual do Norte Fluminense

关键词: carboxilative efficiency;    photosynthetic pigments;    photosynthetic potential;    quantum yield;    respiration     IntroduçãoO princípio básico da produção de biomassa em forrageiras é a transformação da energia solar em compostos orgânicos;    via fotossíntese;    para ser convertida em massa verde;    inicialmente nas folhas (GOMIDE;    1973);   

DOI  :  10.1590/S1516-35982001000800003

学科分类：兽医学

来源: Universidade Federal de Vicosa

【 摘 要 】

- Photosynthetic pigment content, specific leaf mass (SLM) and carboxilative efficiency curves were obtained in response to sunlight in eight genotypes of elephantgrass selected according to productivities during the rainy season: cv. mineiro, CNPGL 91-01-2, CNPGL 91-02-4, CNPGL 91-19-1, cv. taiwan A-146, CNPGL 91-27-5, CNPGL 91-27-1 and CNPGL 91-10-2. Photosynthetic pigments were highly correlated, as well as chlorophyll a/b ratio (ABR) and chlorophyll/carotenoid ratio (CCR). Chlorophyll a and b contents were highest in taiwan A-146 genotype. SLM values indicated smaller dry matter accumulation by unit area for CNPGL 91-27-5 and CNPGL 91-27-1. Establishment of carboxilative efficiency curves of the genotypes allowed the determination of dark respiration rate (Rd), light compensation point (Ic), quantum yield (f) and maximum carbon photosynthetic assimilation (Amax) in light saturation. The taiwan A-146 and mineiro genotypes presented, respectively, about 18% and 11% more carboxilative capacity that the other genotypes. Genotypes taiwan A-146 and CNPGL 91-27-5 showed values of quantum yield (f) close to the average values reported for plants C4. Dark respiration rates varied between 1.64 and 3.38 µmol m-2 s-1 and Ic varied from 26.39 to 54.97 µmol m-2 s-1 in the eight genotypes. This study revealed that, under non limiting irradiance and temperature conditions, genotype taiwan A-146 presented highest photosynthetic rates.

【 授权许可】

CC BY-NC