Enhancement of 20-hydroxyecdysone production in cell suspension cultures of Vitex glabrata R.Br. by precursors feeding

The effect of ecdysteroid precursors feeding on cell growth and 20-hydroxyecdysone production of Vitex glabrata suspension cultures were studied. On the addition of cholesterol, there was no apparentincrease of 20-hydroxyecdysone while growth was partially inhibited at higher levels. Feeding of 7-dehydrocholesterol and ergosterol did not affect the cell growth. Both precursors effectively increased production of 20-hydroxyecdysone. Feeding of 7-dehydrocholesterol as a precursor was most effective. The maximum 20-hydroxyecdysone productivity of about 1.31 mg/L/day was observed in culture with 10 mg/L 7-dehydrocholesterol. This data is the first indication that 7-dehydrocholesterol and ergosterolfeeding are effective precursors for 20-hydroxyecdysone formation in plant cell suspension culture

Effect of salt stress on growth, inorganic ion and proline accumulation in Thai aromatic rice, Khao Dawk Mali 105, callus culture

The inhibitory effect of salt stress in rice is complex and is one of the main reasons for reduction of plant growth and crop productivity. In the present study, the response of rice callus cultivar Khao Dawk Mali 105 (KDML105), commonly known as Thai jasmine rice, to salt stress was examined. Calluscultures of KDML105 rice were exposed to salt stress by placing on Murashige and Skoog (MS) medium containing 250 mM NaCl. Growth, water content, proline and inorganic ion content in rice cells weremeasured during stress treatment for 8 - 10 days. After prolonged exposure to salt stress, growth and water content of rice cells were progressively decreased. Rice cells accumulated high level of Na+during stress, whereas the accumulation of K+ and Ca2+ was decreased. High level of Na+ inside the cells inhibited the K+ uptake resulted in increase level of the Na+/K+ ratio. In addition, salt stress alsocaused an increase in the accumulation of proline. This result suggested that proline may play a crucial role in protecting the KDML105 rice cells under salt stress