Floral Biology and Pollen Viability of Passiflora edulis Sims

Abstract

Yellow passion fruit is a native tropical fruit tree whose cultivation has evolved very rapidly in Brazil; therefore, studies on the ecology of reproduction are needed. The study of pollen viability is an important tool to observe the male potential of the species. The objective of this study was to estimate pollen viability, pollen/ovule ratio and floral biology of Passiflora edulis Sims in organic cultivation located in Bananeiras, PB, and Brazilian. The study was developed in a completely randomized design, using ten flower buds in the pre-anthesis. The analyses performed in the biology laboratory of the Center of Human, Social and Agrarian Sciences of the Federal University of Paraiba. For the pollen viability analysis, all the anthers of the ten flower buds were used, five anthers per flower, which were crushed on a glass slide and with the aid of Alexander dye, the purple pollen grains were considered viable and the green ones unviable. To measure flower morphology and biometrics, a digital pachymeter, analytical balance and ruler were used. Five stamens form the androecium; the fillets are of short length inserted below the ovary. The flowers have three stigmas with an average height of 16.5mm, an average of 32,136 viable pollens, 58 unviable pollen grains and 140 ovules per ovary, having a pollen viability of 99.8% and a pollen/ovule ratio of approximately 95/1 pollen grains per ovule. Their structures are uniform, with no biometric variations in the amount of petals, sepals, anthers and stigma length. Alexander's reactive dye was effective in staining the pollen grains of yellow passion fruit. The pollen/ovule ratio indicates that this species performs facultative autogamy as well; however, this classification alone is not sufficient to affirm its reproductive system.