Differential effects of sucrose, glucose and fructose during somatic embryogenesis in asparagus

Abstract

Summary The effects of different carbohydrates (CHO) were studied during somatic embryogenesis in Asparagus officinalis L. When 1.5 mg · L -1 2,4-D + 0.3 mg · L -1 2ip and 2-6 % glucose, sucrose, or fructose were used in induction media, the average number of embryos was 1286, 719 and 515 g -1 callus, respectively relative to CHO type. On a low-auxin subculture medium, 0.08 mg × L -1 NAA + 0.2 mg · L -1 2ip, the average number of somatic embryos was 38, 310 and 262 for glucose, sucrose, and fructose, respectively. In general, glucose promoted root growth, fructose promoted shoots, and sucrose promoted both shoot and root growth. The CHO concentration was also important to maturation and germination. Average germination rate over CHO concentrations of 2 % and 5 % was 1.8 and 7.4 plantlets g -1 of callus, respectively. The combination of 5 % sucrose in embryo induction medium and 5 % fructose in subculture medium gave the highest germination rate; 10.2 plantlets g-' of callus.