• G Shivaramaiah

      Articles written in Proceedings – Section B

    • A contribution to the embryology ofOldenlandia umbellata Linn.

      G Shivaramaiah S Sundara Rajan

      More Details Abstract Fulltext PDF

      The embryology ofOldenlandia umbellata Linn. has been investigated. Floral parts arise in acropetalous succession. A transection of an young anther shows a group of microscope mother cells followed by a layer of tapetum, a middle layer, an endothecium and an epidermis. The uninucleate tapetum is of the glandular type. Microspore tetrads are tetrahedral and isobilateral. The pollen grain is binucleate at the time of anther dehiscence and the endothecium fibrillar. A hypodermal archesporial cell directly functions as the megaspore mother cell. Embryo sac development follows the Polygonum type. Fertilisation is porogamous. Endosperm is free nuclear and embryogeny conforms to the solanad type.

    • Reverse polarity inNauclea orientalis, L. (Sarcocephalus cordatus, Miq.)

      S Sundara Rajan G Shivaramaiah N Sathyananda

      More Details Abstract Fulltext PDF

      Embryo sac development conforms to Polygonum type. Starch grains are noticed in the embryo sac right from the megaspore mother cell stage. Twin tetrads one with a chalazal functional megaspore and another with a micropylar functional megaspore have been noticed in some ovules. While 75% of the embryo sacs have normal polarity, in 20% of the ovules reverse polarity has been noticed. In the remaining 5% of the ovules, ‘bipolarity’ has been observed. Reverse polarity in relation to double archegoniate theory has been discussed.

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