Effects of temperature and storage under room conditions on the germination of Thrinax parviflora Swartz. (Arecaceae) seeds

Abstract

Thrinax parviflora Swartz is a member of the Arecaceae family and a native to Jamaica. The leaves are palmate, the stipe is narrow, with a diameter of about 5 cm, and the inflorescence arises among the leaves, long and pendent. The fruits are attractive, small and white when mature. Although it is very ornamental, with potential for use in parks and gardens, and also in pots, it is still little known in Brazil. The propagation is from seeds but the information in the literature about the temperature for high germination and the period of time that these seeds could be stored, after harvest, without significant viability losses is rather scarce. The experiments herein reported had the objectives of verifying the effects of temperature and period of storage in laboratory ambient conditions on germination of Thrinax parviflora seeds. The experiment to determine the best temperature for seed germination was installed on April 2, 2002 and lasted till August 8, 2002. The experiment to study the effect of storage was installed on Apriland lasted till September 9, 2002. The seed water content (28.75%) was determined. The first experiment was set up according to a completely random design (constant of 20 °C, 25 °C, 30 °C, 35 °C, and alternate of 20-30 °C and 25-35 °C, with a photoperiod of 2 hours), with four repetitions of 25 diaspores. The diaspores were placed in plastic boxes containing sand. The second experiment was also conducted according to a completely random design withtreatments (sowings made every day starting from the harvest day till 0 days later) with four repetitions of 25 diaspores, placed in plastic boxes containing vermiculite, under 30 °C. The diaspores that emitted the germinative knob were daily counted. The germination percentage and the speed of germination index were calculated until stabilization of the germinative process. The highest germination values were obtained at 35 °C (80%) or 30 °C (65%). Seed storage improved germination from 68% at the day the seeds were harvested to 94% at four and five days after harvest. Seeds stored for 0 days were still germinating 92%. This improving of seed germination with storage is thought to be due to the seeds being not fully mature when harvest took place.Additional keywords: sexual propagation; palms; ornamentals.