http://www.erepo.iihr.ernet.in/handle/123456789/43 2013-05-16T00:46:07Z http://www.erepo.iihr.ernet.in/handle/123456789/241 Title: Spongy tissue in Alphonso mango - significance of in situ seed germination events. Authors: Ravindra, V.; Shivashankar, S. Abstract: Spongy tissue (internal breakdown) of Alphonso mango is a physiological disorder that effects the fruit mesocarp without any external symptoms, posing a challenge for its export. Extensive studies conducted over the past several years on various aspects including physiological and biochemical changes in the fruit mesocarp, failed to provide any conclusive evidence for the origin of the malady. A major shift of focus from mesocarp to the seed indicated that the recalcitrant nature of the seed signals the initiation of in situ germination events at fruit maturity. The consequent physiological and biochemical events associated with it, influence spongy tissue formation. The results showed that drain of water and Ca2+ from the mesocarp to the seed during the process of germination deprive it of the same leading to formation of the spongy tissue in Alphonso mango. 2004-01-01T00:00:00Z http://www.erepo.iihr.ernet.in/handle/123456789/182 Title: Response of grape rootstocks to salinity: changes in root growth, polyamines and abscisic acid. Authors: K K, Uppreti; G S R, Murti Abstract: Effects of salinity (0, 50, 100 and 250 mM NaCl) on growth, root:shoot dry mass ratio, osmotic potential (ψπ),electrolyte leakage and contents of Na+ and K+, polyamines and abscisic acid (ABA) were studied in the grape rootstocks Dogridge, 1613, St. George and Salt Creek. In control rootstocks, the root length was highest in Dogridge and contents of K+ and ABA in Salt Creek. Salinity treatments increased root Na+ and decreased K+ content and St. George exhibited highest Na+ content and Na+:K+ ratio. The root:shoot dry mass ratio in all rootstocks increased upto 100 mM NaCl. With increasing NaCl concentration, putrescine, spermine and spermidine contents showed consistent increase and putrescine increase was highest in St. George and spermidine and spermine in the Dogridge and Salt Creek. Under salinity, the ABA content increased in all the rootstocks but more in Salt Creek and Dogridge than in St. George. 2010-01-01T00:00:00Z http://www.erepo.iihr.ernet.in/handle/123456789/166 Title: Floral abscission and changes in sucrose phosphate synthase and invertase activities in water deficient tomato Authors: R M, Bhatt; N K, Srinivasa Rao; K K, Upretti; H S, Shoba Abstract: A study was conducted to determine the photosynthesis, sucrose phosphate synthase and invertase activities in four tomato (Lycopersicon esculentum Mill) cultivars, e.g. Mruthyunjaya, Pusa early dwarf (PED), Arka Ahuthi and Pusa Ruby exhibiting differential response in floral abscission under water stress. Among the four cultivars, Arka Ahuthi and Pusa Ruby were found to be more susceptible to abscission under water stress as indicated by more than 55.0% abscission flower buds and flowers in these cultivars. Water stress caused a substantial decrease in photosynthesis in all the cultivars, although the degree of decrease varied with cultivars. IN the cultivars where the abscission of flowers and flower buds was more (ARka Ahuthi and Pusa Ruby), the reduction in photosynthesis was more (53-61.5%) compared to the cultivars where the abscission was relatively less (Mruthyuinjaya and PED) (39.0-53.0%) during stress. There was a considerable decrease in SPS activity in reproductive organs as well as leaf and developing young fruits decreased under stress. The decrease in photosynthesis along with a reduction in invertase activity may be important contributing factors for the abscission for flower and flower buds in abscission susceptible tomato cultivars under water stress. 2009-01-01T00:00:00Z http://www.erepo.iihr.ernet.in/handle/123456789/165 Title: Hormonal activity in tomato flowers in relation to their abscission under water stress Authors: R M, Bhatt; N K, Srinivasa Rao; K K, Upreti; M Jyothi, Lakshmi Abstract: Ethylene and indole acetic acid (IAA) concentrations were investigated in the flowers of four tomato (Lycopersicon esculentum Mill.) cultivars, e.g. Mruthyunjaya, Pusa Early Dwarf (PED), Pusa Ruby and Arka Ahuthi under water stress, imposed at flowering stage (40 days after transplanting) for a period of one month by withholding irrigation. Arka Ahuthi and Pusa Ruby were found more susceptible to flower abscission compared to Mruthyunjaya and PED under water stress. Ethylene production in the flowers of different varieties increased under stress and ranged from 36.2 to 62.7 nl g-1 h-1, from 15.1 to 19.1 nl g-1 h-1 in the control plants. In the abscission susceptible Arka Ahuthi and Pusa Ruby such increase under the water stress was four times of the control plants. The IAA levels in the flowers under stress decreased to 22.3 – 48.4 ng g-1 from 38.0 -71.0 ng g-1 range in the control plants. The IAA levels in more in the abscission susceptible tomato cultivars. Decrease in IAA level in association with increase in the ethylene level in the flowers might be the important factors causing flower abscission under water stress. 2009-01-01T00:00:00Z