In Vitro Culture of Wheat Tissues. I. Callus Formation, Organ Redifferentiation and Single Cell Culture

Abstract

Callus induction, organ formation from callus and single callus cell culturc have bcen tried in wheat. Though lcinetin sl~owed no effects, supplemcnts of 2,4-1) (I-lOnig/l) or IAA (jOmg/l) to tlie basal mcdia induced calluses from seedling roots of einl~orn, enlmcr and coninion wtlcats, and from stem pieccs of common \vheat. T h e best caIIus gron;th was olxained when casein liydroIysate ( l g / l ) or coconut milk (1%) was added t o tlic basal media. Callus gl.owtIi n.as also vigorous when 2,4-11 (0.5-2.0rng/l) uras added. Root formation from callus took place in all kinds of tested media, except those containing no growth factors or supplemented \vitli 2,4-D at high concentrations (I-jmg/l).Shoot formation occurred in six cascs and no growth factors wcre found to be specifically cffective on shoot differcntiation. Tv.0 plants were rcstorcd and rcaclictl maturity. Calluses of coninion wheat consisted of eudiploid and ancuploid cells at almost the same frequencies. T h e grcat majority of ancuploid cells had 42 5 3 cliromosonies. T h e restored plants slio\ved normal chromosome constitution. Single callus-cell suspensions \\.ere obtained. b! . thc liquid culture of seeds in a shalcer. A filtrate of tlic single cell suspension was plated o11 a solid agar ti~edi~uii, and some colonies ufcrc formed. Ho\\.cver, plating efficiency uras very l o u~ and colony grou~th was slow.

Chromosome Constitution of Tobacco and Wheat Callus Cells

“…The chromosome constitution of four year-subcultured callus cells which originated from the root of common wheat, was similar to that of one year-subcultured callus cells, whose chromosome number varied from 26 to 84 with predominantly diploid cells (Shimada et al 1969). The present results clearly show that the callus cell population of wheat does not greatly change its chromosome constitution due to continuing subculture.…”

“…The chromosome constitution of callus cells originating from the stem of a common wheat, Triticum aestivum cv. S-615, was also similar to constitutions of callus (Shimada et al 1969) . Therefore, we concluded that, regardless of the source, i.e.…”

“…The result revealed that there is also a large variation in chromosome number among callus cells, ranging from 2n=38 to 153, where a normal cell is expected to have 2n=48. On the contrary, calluses induced from root tips of common wheat showed a very narrow range of variation; about 50% of the cells were euploid (2n=42) and the great majority of the remaining cells were aneuploid, having 42±3 chromosomes (Shimada et al 1969). …”

BEHAVIOR OF UNSTABLE TELOCENTRIC CHROMOSOMES IN CULTURED CALLUS CELLS OF CHINESE SPRING WHEAT (<i>TRITICUM AESTIVUM</i> L.)

“…Figure 1 shows normal and telocentric chromosomes. Variations of chromosome constitutions in common wheat calluses were previously reported (Shimada et al 1969;Asami et al 1972;Shimada et el. 1974;Asami et al 1975;Inomata et a1.1975) .…”

“…It has already been known that chromosome constitutions vary greatly in callus tissues (De Torok and White 1960;De Torok and Roderick 1962;Cooper et al 1964;Nishiyama and Taira 1966;Shimada and Tabata 1967;Heinz et al 1969;Shimada et al 1969;Asami et al 1972;Bayliss 1973;Asami et al 1975). Structural changes of chromosomes in cultured callus cells were previously reported by Kao et al (1970).…”