ABSTRACT
This paper is an introduction to gravitational and space life sciences and a summary of key achievements in the field. Current global research is focused on understanding the effects of gravity/microgravity onmicrobes, cells, plants, animals and humans. It is now established that many plants and animals can progress through several generations in microgravity. Astrobiology is emerging as an exciting field promoting research in biospherics and fabrication of controlled environmental life support systems. India is one of the 14-nation International Space Exploration Coordination Group (2007) that hopes that someday humans may live and work on other planets within the Solar System. The vision statement of the Indian Space Research Organization (ISRO) includes planetary exploration and human spaceflight. While a leader in several fields of space science, India is yet to initiate serious research in gravitational and life sciences. Suggestions are made here for establishing a full-fledged Indian space life sciences programme.
ABSTRACT
The endosperm and embryo that constitute the filial tissues of rice caryopsis are isolated from the maternal tissues by the absence of any symplastic continuity. Nutrients are transported to the endosperm through a single ovular vascular trace present on the ventral side of the ovary. Initially solute enters through the chalaza into the nucellar projection and then into the endosperm. At later stages transport occurs through the nucellar epidermis, centripetally towards the endosperm. The cell walls of the nucellar epidermis are provided with rib-like thicken ings. A comparison of grain-filling in C3 and C4 cereals suggests that rice has structural features allied to C3 cereals, such as wheat, but with significant differences.