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APICAL FOLIAR NECTARY OF POMEGRANATE (PUNICA GRANATUM: PUNICACEAE)
Author(s) -
Turner Glenn W.,
Lersten Nels R.
Publication year - 1983
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1983.tb07875.x
Subject(s) - nectar , biology , apex (geometry) , phloem , botany , xylem , epidermis (zoology) , staining , anatomy , pollen , genetics
This is the first report of an extrafloral nectary in the Punicaceae. Each leaf of pomegranate bears a single apical nectary that consists of a closely packed spherical mass of densely staining cells, and of a surrounding layer of cells that are larger and more vacuolate, though still densely staining. The epidermis at the apex of the nectary (which is also comprised of small, densely staining cells) bulges to form a bump over a small chamber. The leaf apex lacks stomata or other specialized pores for nectar to escape. However, separation of epidermal cells and conspicuous ruptures sometimes occur. The midvein and 2–4 lateral bundles converge on the nectary. The xylem stops before reaching the nectary, but the phloem continues, curving about halfway around the nectariferous tissue. Chromatographic analysis of nectar droplets showed roughly equal amounts of fructose, glucose, and sucrose. This nectary resembles leaf apical glands of Lafoensia in the closely related family Lythraceae.