Lianas da floresta estacional semidecidual: ecofisiologia e uso em restauração ecológica

Abstract

Lianas are important components of the structure and dynamics in seasonally dry forests, but there are few studies on their ecophysiology and use in restoration ecology. The objective of this study was to evaluate the ecophysiology of seeds and juveniles of species of liana in the preferences for environmental regeneration and the variables involved in using these species in direct seeding in restoration ecology. Seeds of 11 liana species were submitted to germination test in a combination of light and dark conditions with constant and alternating temperatures, with 4 replicates of 25 seeds per treatment. Seedlings growth was evaluated for eight liana species in conditions of full sun light and shading, with 12 repetitions per treatment. The plants were evaluated according to the dry mass of leaves, stem and root , as well to the number of leaves per plant. For the study of direct seeding, 400 seeds of three liana species were sowed under the canopy of four tree species present in a 20-year-old restored forest in Iracemápolis - SP. Evaluation was performed monthly and for a period of 210 days by accounting seedling emergence. The species Bauhinia sp, Pithecoctenium echinatum and Urvillea laevis did not require light and alternating temperature to germinate, but the species Macfadyena unguis-cati, Mucuna sp 1, Temnadenia violacea, Adenocalymma bracteatum and Hippocratea volubilis showed positive photoblastism and the species Peltastes peltatus, Aristolochia galeata and Cardiospermum grandiflorum required alternating temperatures. All seedlings survived to shading, but most of then grew better under full sun light. Only the species Bauhinia sp Macfadyena unguis-cati produced seedlings in the direct sowing, but at low emergence percentage and rate, which did not differ among tree species canopy. Thus, the studied lianas can have different responses to environmental conditions typical of forest gaps, as some species required light/alternating temperature to germinate and full sun light to grow better, and others were indifferent to such conditions. These results indicate that the ecophysiological characteristics of lianas should be considered when planning their introduction in restoration ecology projects.