Cytological Investigations on the Endosperm of <i>Borassus flabellifer</i> Linn

Abstract

The endosperm serves as the main source of nutrition for the developing embryo and its failure results in the abortion of embryo and consequently low fertility. Economically, the tissue is of great importance since it is the store house of carbohydrates, proteins, lipids and growth regulating substances. Although much work has been done on the morphology and physiology of this tissue in a number of angiosperms, the record of cytological investigations on this is relatively meagre. The very interesting findings made on the cytology of coconut endo sperm in this laboratory (Abraham 1963, Abrahm and Mathew 1963, Abraham , Ninan and Gopinath 1965, 1966) gave inspiration to inquire into the cytological situations in the endosperm of allied genera. The observations made on the cytology of the endosperm in Palmyrah palm (Borassus flabellifer Linn.) are presented in this paper. Material and methodsThe endosperm for the present work was collected from palmyrah palms from a few localities in Trivandrum District. Endosperm at various stages of develop ment was fixed in Carnoy's fluid in the noon hours and after a few changes of fixative acetocarmine smears were made.The liquid endosperm found in the central cavity of the developing seeds was sucked out using hypodermic needle and to it was added Carnoy's fluid and then it was subjected to centrifugation at 250rpm for two hours. The sediment was again fixed in Carnoy's fluid and acetocarmine smears were made.In order to study the development of the endosperm 1 to 20 week old intact seeds were fixed in F . A. A. and microtome sections were made by the usual paraffin method. The slides were stained with iron haematoxylin and fast green.To ascertain the chromosome number of Borassus flabellifer Linn. growing em bryos from 4 to 5 month old nuts were fixed in Carnoy's fluid in the noon hours and acetocarmine smears were made. ObservationsThe chromosome number of the species was ascertained as 2n (2x)=36 (Fig. 1). The earliest recognizable stage in endosperm development is the occurrence of

Mechanisms of endopolyploidization in Datura endosperm.

“…The third mechanism is the 'C-mitotic type of division ' (Abraham and Ma thew 1963) caused by the blockage of spindle activity at metaphase. This has been observed in the endosperm of Borassus flabellifer (Stephen 1974) and Haemanthus katherinae (Stephen 1979). This corresponds to 'metareduplication' of Hsu and Moorhead (1965) and 'Restitutionkernbildung' of Enzenberg (1961).…”

EL CICLO CELULAR EN VEGETALES. Su estudio, importancia y aplicaciones.

“…mitosis con diplocro*oro*or, iíil-uo: fusión de los núcleos en las mitosis con diplocromosotnas. ( D'Amato, I 977 )' (Stephen, 1974 (D'Amato, 1977). En la Fig.…”

Genome variability of plant somatic cells. 1. Variability during ontogenesis

“…Рассмотрим динамику этого явления на примере формирования нуклеарного эндосперма у некоторых, главным образом, однодольных растений [19,[22][23][24][25][26][27], учитывая при этом, что сходная картина отме чается и у двудольных, в том числе и у тех, у которых эндосперм в зна чительной мере редуцирован, например, у ряда представителей рода Lathyrus [28,29].…”