Morfometria, crescimento e produção de Jacaranda decurrens Cham. ssp. symmetrifoliolata Farias & Proença (Bignoniaceae)

Abstract

Data of morphometric of fruits and seeds, although they still are scarce, are important for studying genetic improvement of populations, as well for improvement of storage conditions and for improvement of seedling yield. In order to subsidizing the knowledge of Jacaranda decurrens ssp. symmetrifoliolata (carobinha), this research had as aims to evaluate morphometric of fruits, seeds and seedlings and germinative potential of seeds that were stored in different periods, at environmental temperature. Morphometrical study of fruits and seeds was done in February, 2007, at UFGD, in Dourados, MS. In a sample of 116 fruits that were gathered in aleatory way from a populations of 25 plants, mass, length, width and thickness, besides the counting of seeds per fruit, were determined. In biometrical analysis of seeds, a sample with 550 seeds which was gathered in aleatory way from fruits was used, and length, width and thickness were measured. Germination was studied after three periods of storage of seeds (120, 480 and 720 days) and in four temperatures of germination, which three of them were constant (18, 25 and 30ºC, under constant light) and one alternated (20-30ºC under light, with photoperiod of 12 hours day/night). Treatments were arranged in 3 x 4 factorial scheme on a complete randomized design with three replications. Seedling development was evaluated 35 days after sowing, in which measurement of length of root and stalk. Carobinha fruits showed great variability of mass, length, width, thickness and number of seeds, which averages were 45.5 g, 86.5 mm, 62.7 mm, 18.2 mm, respectively. Averages for length, width and thickness of seeds were 9.2mm, 8.8 mm and 1.5mm, respectively. Percentage of germination and velocity of germination of seeds that were stored under environmental temperature were influenced significantly by periods of storage, which the greatest averages were registered under temperature of 25ºC (69.4% and 0.983). Seeds that were stored for 480 and 720 days, under environmental temperature lost completely vigor. Carobinha seedlings showed hypogeal germination, conforming in crypto cotyledonal type. The development of root and stalk was higher at 25ºC, but eophyls of seedlings that were germinated under temperatures of 30ºC and alternated showed themselves more developed.