Role of PGrs and inhibitors in induction and control of somatic embryogenesis in Themeda quadrivalvis.

Somatic embryogenesis could be achieved in Themeda quadrivalvis (Linn.) O. Ktze -fodder grass species on MS medium supplemented with 2,4-D. Incorporation of putrescine in the medium stimulated embryogenesis, however its lower concentration stimulated production of non-regenerative callus. Other polyamines such as spermine and spermidine could not evoke similar response. Ascorbic acid used as antioxidant could not prevent browning in embryogenic cultures, however it stimulated embryogenesis. Inhibition of auxin polar transport by use of TIBA and HFCA reduced the embryogenic response significantly and produced distorted or abnormal embryos. Antiethylene substances such as AgNO3 and CoCl2 added in the medium adversely affected the process of embryogenesis and counteracting the stimulatory role of ethylene.

In vitro growth and shoot multiplication in Terminalia bellerica roxB. under controlled carbon dioxide environment.

The shoot cultures of Terminalia bellerica Roxb. were grown on Murashige and Skoog's medium containing 1.5 mg 1(-1) BAP (6- benzyl aminopurine), and supplemented with or without sucrose (3%). A range of CO2 concentrations (0.0, 0.6, 10, 40 g(-3)) was provided in small acrylic chambers by using different concentrations and combinations of NaHCO3 (sodium bicarbonate), Na2CO3 (sodium carbonate), KHCO3 (potassium bicarbonate) and K2CO3 (potassium carbonate). To obtain a CO2-free environment, a saturated solution of 10% of KOH (potassium hydroxide) was kept in the chamber. Complete absence of carbon source caused death of shoots within 20 days. Under controlled and enriched CO2, the shoots grew fully photoautotropically on sucrose-free medium. The growth of cultures was better with carbon dioxide (40 g(-3)) than sucrose (3%) in the medium. Maximum number of shoots, number of leaves per cluster, fresh and dry weight and chlorophyll contents were recorded when both sucrose and CO2 (40 g(-3)) were provided to the culture.