Estudo dos nectários das flôres de Sechium edule Sw.

Abstract

This paper is related with pollination studies made in 1964, at the Bee Keeping Department of "Luiz de Queiroz" Agricultural College. The objective was to study and compare morphological, anatomically, as well as the secretion functions of male and female flower nectaries of Sechium edule Sw., commonly known as "chuchu". In the morphological study we verified the placing and number of nectariferous cavities, size, and type of the nectaries. In the anatomical study we observed the placing and structure of the nectariferous tissue. In respect to the function, observations were made on secretion, the time of day in which it occurs, and quantity of nectar produced. We compared the nectaries of male and female flowers and obtained the following results: 1. Morphological 1.1. The nectaries of male and female flowers do not differ as to form and position but as to size. In female flowers they are larger. 1.2. In female flowers the wall that separates the nectary pair may be incomplete, not reaching the surface. In this case the fusion of both pairs occurs. 2. Anatomical 2.1. It is assumed that the nectariferous tissue of a region compound of some cells layers retain the dye "Fast Green" more intensely disclosing a denser citoplasm. In that region there are cells that produce sugar (glucose and levulose) as repeatedly proven by Fehling's liquor reaction. 3. Secretion function 3.1. The nectar is expelled principally by the globule emergence from the delicate epidermis. 3.2. We did not exclude the possibility of nectar secretion behind the existant glandular hairs in the periphery of the nectariferous cavities. 3.3. The secreted nectar which is collected by the insects in the early morning, emerges from the opening of the nectariferous cavity in the from of little drops. 3.4. The volume of secreted nectar varies according to the environmental conditions. 3.5. In one test, which consisted of 6 flowers, only 10 microliters (1 microliter is equal to one thousandth of a ml.) were obtained. On that same day the same quantity of nectar was obtained from male and female flowers.