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Fossilized pollination droplet in a new seed genus from the Middle Triassic of Nidpur, India

100%

Bhowmik N. , Parveen S.

tom 59

nr 2

The present article reports a fossilized pollination droplet at the micropylar orifice in a compressed seed Gopadispermum papillatus gen. et sp. nov. from the Middle Triassic beds of Nidpur, Madhya Pradesh, India. The shapeless droplet forming a convexity above the micropylar orifice is comprised of a resinous crystalline substance. Entrapped within the droplet are a few saccate pollen grains. The seeds are small, oblong to widely elliptical in shape, about 3 mm long and generally 2 mm broad. The micropylar end shows a short straight beak-like micropyle often extended beyond a persistently adhering wrinkled tissue lying outside the seed coat. The seed is composed of four membranes excluding the adherent tissue. They are the outer and inner cuticles of integument, the nucellar cuticle distally modified to form a dark collar-like pollen chamber and the innermost megaspore membrane. Cuticles of the tissue adhering to seed coat are different from seed coat cuticles. The pollen grains inside the pollen chamber are frequently clumped together forming a pollen mass. Individual pollen grains appear spheroidal to ellipsoidal in shape and are saccate. This is the first report of the preservation of a pollination droplet in a compressed seed specimen from the Nidpur Triassic beds. Preservation of the droplet can be attributed to its supposed resinous constitution and the entrapped organic contents (pollen grains). Occurrence of clumped pollen grains inside the pollen chamber also indicated possibility of fluid feeding, pollinivory and insect pollination in the seeds.

A micropropagation protocol for Cassia angustifolia Vahl. from root explants

100%

Parveen S. , Shahzad A.

Acta Physiologiae Plantarum

2011

tom 33

nr 3

The aim of this study was to develop a new micropropagation system for Cassia angustifolia Vahl., an important medicinal legume using root explant as starting material. Root explants taken from 30-day-old aseptic seedlings were cultured on Murashige and Skoog (MS) medium supplemented with different plant growth regulators: 6-benzyladenine (BA), kinetin (Kn), and thidiazuron (TDZ). Organogenic nodular calli obtained on MS + TDZ (1.0 µM) were transferred to shoot regeneration medium supplemented with different cytokinins (BA, Kn or TDZ) either alone or in combination with auxin:indole-3-acetic acid or a-naphthalene acetic acid. Maximum shoot regeneration frequency (90%) was obtained on MS + BA (2.5 µM) + NAA (0.6 µM) wherein a maximum of 42.76 ± 1.47 shoot buds per explant were induced with a maximum conversion rate of 35.63 ± 0.75 shoots per explant and average shoot length of 5.43 ± 0.20 cm. Elongated microshoots were successfully rooted under ex vitro conditions by pulse treatment in 200 µM of indole-3-butyric acid for half an hour. Microshoots were rooted, acclimatized and hardened off simultaneously in sterilized soilrite inside the growth room and then established in pots containing sterilized soil and manure (1:1) and grown under greenhouse condition with 90% survival rate. The histological sections at different developmental stages of shoot buds revealed the organization of nodular meristematic zone leading to the orientation and differentiation of shoot buds in large number and thereafter conversion into healthy shoots.