Further Studies on the Photosynthesis of Carrot Tissue Cultures

Abstract

The influence of kinetin and sucrose on (60%), Hill activity (about 3-fold), and "C-fixation from NaH"CO3 (about 20%). On the other hand, the presence of sucrose in the medium reduced the chlorophyll content by about 30% and "C-fixation from NaH"4CO3 in the soluble fraction by about 60%. A possible correlation between the influence of kinetin on sugar uptake and the effect of kinetin on "C-fixation from NaH"CO3 was discussed.

Aspects of Photosynthetic Plant Tissue Cultures

“…Sucrose requirement or sucrose repression? A number of studies have shown that the addition of sucrose to the culture medium reduces the ChI content of plant cell cultures in both callus (9,11,12,13) and suspension cultures (14). In our hands, comparing ChI levels in photoautotrophic soybean suspension cultures (no sucrose, 5% CO 2 ) to that in photomixotrophic suspensions (1% sucrose) reveals a ChI reduction of approximately 50% (15).…”

“…By most accounts a cytokinin is required for cultured cells to accumulate and maintain ChI (5,18,21,22,23,24,25) as well as to develop structurally normal chloroplasts (25,26) which contain a full photosystem complement (23). In at least one report (13), a cytokinin was not absolutely required for greening but the inclusion of 0.1 mg/l kinetin resulted in a 60% increase in ChI. In another report, chloroplasts in a trutant Petunia cell line (AK-240l) accumulated ChI and formed grana stacks in the dark if 1 mg/l 6-benzylaminopurine (BA) was added (26,27).…”

An Improved Medium for the Photoautotrophic Culture ofCytisus scopariusLink Cells

“…Possibly, cytokinin affects green cell growth directly by stimulating photosynthetic activity. 13) We investigated the conditions needed for vigorous photoautotrophic growth and had partial success. Green Phellodendron cells, which had a high chlorophyll content, could not grow photoautotrophically under any of the conditions tested here.…”

Growth regulation, plastid differentiation and the development of a photosynthetic system in cultured carrot root explants as influenced by exogenous sucrose and various phytohormones

“…The most important factors are light, nutritional status and hormonal supply. Although several autotrophic cultures of green cells have been reported (22), a sugar supplement is usually needed in the medium for maximal growth of cells [6,[11][12][13][16][17][18]. However, a sucrose supplement to the nutrient solution usually decreases chlorophyll content and activity in CO2-fixation [16,17].…”

“…Although several autotrophic cultures of green cells have been reported (22), a sugar supplement is usually needed in the medium for maximal growth of cells [6,[11][12][13][16][17][18]. However, a sucrose supplement to the nutrient solution usually decreases chlorophyll content and activity in CO2-fixation [16,17]. To understand the rote of nutritional factors during callus induction and growth, it seems to be important to correlate the effects of sugar with that of hormones on growth and chloroplast development.…”