Studies on palms: embryology of Phoenix sylvestris Roxb.

Abstract

The paper gives an account of the embryology of the genus Phoenix Linn. being intensively studied in this Department. Phoenix sylvestris Roxb. has been investigated as a type. Male and female flowers, pollen grains, development of ovule, male and female gametophytes, endosperm and embryo development were worked out. The plants are dioeceous, 10-16 m. in height, with rough trunk due to persistent leaf bases. Both the inflorescences are spadix, each arising in the axil of a leaf in acropetal succession. There are 6-8 spadices at a time on a tree. The smooth and round pollen grains are shed in 2-celled condition. The ovules are anatropous, bitegmic and crassinucellate. The endosperm is nuclear to begin with but becomes cellular later. The embryo develops according to theGeum variation of the Asterad type. It shows a definite tendency towards forming two cotyledons in early stages, but only one becomes massive later and attains maturity. The shoot apex is terminal. The micropyle shifts from terminal to lateral position. Besides this species,P. pusilla, P. robusta, P. acaulis and P. reclinata were also studied and they show the same pattern of embryo-sac and embryo development with certain variations.