Resumo

AMADOR-ALFEREZ, Karina Alejandra; DIAZ-GONZALEZ, Josefina; LOZA-CORNEJO, Sofía  e  BIVIAN-CASTRO, Egla Yareth. Effect of plant growth regulators on seed germination and seedling development of two Ferocactus species (Cactaceae). Polibotánica [online]. 2013, n.35, pp.109-131. ISSN 1405-2768.

The effect of the addition of three plant growth regulators (PGRs) on the germinative response of seeds and seedlings development in Ferocactus histrix and F. latispinus (Cactaceae) was evaluated. Lots of seeds were germinated with the addition of different concentrations (125, 250, 500 ppm) of indole acetic acid (IAA), naftalen acetic acid (NAA) and gibberellic acid (GA₃); seeds not treated with PGRs were also sown in distilled water as controls. The percentage of seed germinated (% G), velocity index of germination (IVG), regression coefficients and quantitative morphological characters of initial growth seedlings were recorded each third day during 30 days of laboratory trials. The results showed significant differences (Tukey, P < 0.05) between PGRs treatments and the control, and a negative effect of PGRs on the %G and seedling growth. The highest percentages of germination (55-75%) were observed for both species with control treatment. At concentration of125 ppm, IAA promoted 51% of germination in F. latispinus at ninth day. 62% of germination for F. histrix was registered at sixth day with NAA (250 ppm) treatment, and the least germination percentage (< 40%) was observed in both species with the GA3 treatments (125 and 250 ppm), respectively. It was concluded that PGRs addition did not significantly increase germination (%G and germination speed) over untreated seeds in these two Ferocactus species. Also, PGRs treatments not contribute to enhance the growth since the higher and vigorous seed-lings in both species were obtained with the control treatment.

Palavras-chave : plant growth regulators; Ferocactus histrix; Ferocactus latispinus; Cactaceae; germination.

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