Pineapple has recently started blooming in the Botanical Garden. The pineapple is a species of the family Bromeliaceae. Most of the species in this family live as epiphytes (plants that grow harmlessly upon another plant) in tropical and sub-tropical America. Plants that grow under the tropical forest canopy compete for the limited sunlight that penetrates the forest canopy. Epiphytes avoid this competition by growing on the top of tall tree branches, and thus don’t need to invest the energy required to develop a tall stem and branches. A large and diverse collection of bromelid species can be seen in the Garden’s tropical house, most growing as epiphytes on artificial tree-like constructions. The pineapple is an exception in its family, growing on the ground. It is a perennial plant with dentate and spiky leaves, whose habitat is southern Brazil and Paraguay. Its inflorescence comprises many pinkish flowers, pollinated by hummingbirds. Flowering in pineapple can be induced by increasing the concentration of ethylene gas. Moshe Peri, our chief gardener and the tropical house manager, increases ethylene concentration by using rotten apples (which secrete ethylene) - and with great success! The plant sets flowers in the garden once every three years.
Pineapple is a multiple fruit, constructed of many hexagon-shaped small individual fruits, each originating from one flower. The fruit can be developed even without pollination, producing a seedless fruit, just like bananas. The seeds, when present, are small and hard and undesired by commercial growers. Thus, most of the agricultural reproduction of pineapples is carried out vegetatively from cuttings.
During the next few weeks the flowers and the developed fruit will be on show in the Dafna Carasso Tropical House. Come and see them growing!