Using Haworthia Cultured Cells as an Aid in Teaching Botany

Abstract

IDUCTION OF TISSUE CULTURES from monocotyledons for morphogenetic studies in the developmental botany or advanced botany laboratory is a problem often faced by many instructors and students. This is because information on monocotyledons tissue culture is limited (Shimada et al. 1969). The recent introduction of a technique to induce callus cultures from several species of the genus Haworthia offers a suitable method to study monocotyledon cell morphogenesis in vitro (Majumdar and Sabharwal 1968; Majumdar 1970a, 1970b, 1970c). The genus Haworthia a member of the tribe Aloineae and family Liliaceae, is a common succulent native to the South African region. (Haworthia species may be obtained from the International Succulent Institute of Millbrae, California, USA.) It is found in many greenhouses, homes, and biological supply houses in the United States (fig. 1). The species are easily maintained in the laboratory, and they flower several times a year. The cytogenetics of Haworthia is well known (Majumdar and Riley 1973). Recently, calluses induced from Haworthia on culture media have been used to study morphogenesis and to observe the effects of mutagens and carcinogens on chromosomes, cells, and cell organelles (Kaul and Sabharwal 1975; Majumdar and Schlosser 1971; Majumdar and Newton 1972; Sullender and Majumdar 1975). The species are also suitable for plant developmental studies since the time required for callus induction on defined media is very short-two to three weeks. Vegetative bud production and subsequent differentiation of the callus into roots and leafy shoots can be obtained in 'five to six weeks after initial inoculation. In our research we have successfully induced callus cultures from flower axes, flowers, and ovary walls from several species of Haworthia.