Seed germination of Southern Chihuahuan desert cacti: Effect of mucilage, light and phytohormones Article uri icon

abstract

  • The aim of this study was to evaluate the effect of mucilage and its removal, as well as phytohormones [gibberellic acid (GA3) and indole-3-acetic acid (IAA)] in light and in darkness on germination of five cactus species (Coryphanta maiz-tablasensis, Echinocactus platyacanthus, Ferocactus latispinus, Ferocactus pilosus and Stenocereus queretaroensis) from the Chihuahuan Desert. Three of them, C. maiz-tablasensis, E. platyacanthus and F. pilosus, are at risk. The mucilage layer occurred in all species. The sterilization treatment removed the mucilage even from the micropyle. Mucilage resulted in higher germination percentage in E. platyacanthus (88.5 %25 vs. 21.1 %25 without mucilage), F. latispinus (88.5 %25 vs. 48.2 %25) and S. queretaroensis (96.0 %25 vs. 1.0 %25), as well as a lower germination time for E. platyacanthus (10.0 days vs. 19.5 days without mucilage), F. pilosus (14.1 days vs. 16.4 days) and F. latispinus (7.8 days vs. 14.0 days). GA3 did affect germination percentage in E. platyacanthus (higher at 500 and 1000 mg l−1 than at 50 and 100 mg l−1), F. latispinus (higher at 1000 mg l−1 of GA3 than at the control and at the other concentrations) and F. pilosus (higher at 1000 mg l−1 of GA3 than at control and 50 mg l−1). The interaction of mucilage layer and GA3 was only significant for F. latispinus in that seeds with mucilage had higher germination at 0, 50, 100 and 250 mg l−1 of GA3 than seeds without mucilage, but at 500 and 1000 mg l−1 germination was high with and without mucilage. Most cactus seeds had no germination in darkness and auxins did not promote germination. Mucilage covers the micropyle and seeds without mucilage were internally more colored than seeds with mucilage in most species. We suggest that mucilage layer in the micropyle can function like a barrier regulating the passage of water to the inner seed. © 2019 Elsevier GmbH

publication date

  • 2020-01-01