Effect of regulated stress and its potential implication in Ulva fasciata

Salinity, desiccation, and light deficient stress were the three different stress used to examine the regulated stress effect on Ulva fasciata (Sea lettuce). The interactive effect of time and salinity was recorded in both SOD and Catalase enzyme activity. The overall percent increase of SOD activity was 40%±0.79 and 433%±83.58 in Catalase activity in 100 psu respectively after 72 h. Similarly, the cumulative effect of stress on the activity of antioxidant enzymes was significant in all the test condition. The study showed that regulated stress could enhance protein content significantly. An increase of 317% of protein content was recorded after 48 h of desiccation. The protein concentration in desiccation stress was more by 53.42% and 63.4% than dark and salinity stress. The ability to enhance biotic compound through modulated stress can be an effective way of harnessing and sustainable use of natural resources. The elevated concentration of protein and an antioxidant enzyme activity due to the regulated stress in the present study suggest this possibility. The enhancement of a biologically active compound through regulated stress can be a handy tool for biotech based industry.

In vitro propagation of threatened terrestrial orchid, Malaxis khasiana Soland ex. Swartz through immature seed culture.

Rapid in vitro propagation of the terrestrial orchid, M. khasiana through immature seed culture was achieved. Immature seeds of 8-9 week after pollination (WAP) cultured on MS medium (2% sucrose) supplemented with 500 mgl(-1) casein-hydrolysate and 1 microM N6-benzyladenine (BA) exhibited germination of 75% seeds after 107 days of culture and subsequently supported the development of PLBs. Subsequent culture on MS medium enriched with 6 microM of indole-3-acetic acid (IAA), 18 microM each of BA and kinetin induced multiple shoots and plantlets. Transfer of PLBs to MS medium with 0.1% activated charcoal (AC) facilitated rapid proliferation of PLBs, while AC at 0.2% favored shoot bud induction and rhizome enlargement. The plantlets, developed on medium with IAA, BA and kinetin, after hardening in vitro for 8-10 weeks were planted in community pots and transferred to poly-house. The plantlets showed 65% survival under field conditions.

Regeneration of plantlets from in vitro raised leaf explants of Cleisostoma racimeferum Lindl.

Protocorm like bodies (PLBs), callus and shoot buds developed in culture from in vitro raised foliar explants of Cleisostoma racimeferum. Among the different basal media, better result was obtained on MS medium containing sucrose (3%) and BA (2 microM) with approximately 80% frequency after 40 days of culture. Young leaves (15 week old) produced better PLBs. Whole leaf placed vertically upside-up orientation can regenerate PLBs and shoot buds (80%). PLBs and shoot buds formed on entire surface of the leaves. Cultures on BA and NAA (2 and 2 microM respectively in combination) stimulated callus mediated regeneration (68%). The rooted plantlets regenerated within 8-10 week from PLBs and shoot buds on MS medium containing IAA and kinetin (2 microM each in combination). BA containing medium triggered multiple shoot bud formation, while NAA alone or in combination with other growth regulators was inhibitory. Incorporation of activated charcoal (0.01%) in the medium stimulated formation of repetitive PLBs and multiple shoot buds. Rooted plants were ready for harvest after 20-22 week of initiation of culture. About 65% of the potted plants survived after 3 months in the poly house.