review of the occurrence and tissue culture of carotene pigments in citrus species

ABSTRACT

Carotenoids are the predominant pigments of citrus fruits. Carotenes, cryptoflavin, cryptoxanthin, uterin, luteoxanthins, phytofluene and violaxanthin are the most common carotenoids studied extensively in citrus plants. In early stage of peel formation of Satsuma mandarin fruits, diol and hydrocarbons were most abundant carotenoid groups followed by polyol, diol, epoxide and monols. Sannen independently discovered that pale colouration of Turkish Satsuma mandarin fruits was due to lack of deep coloured carotenoids such as beta-citraurine and /beta-apo-8'carotenal. Interstocks significantly affected beta-carotene and lycopene in the peel and pulp of grapefruit on C. reshni stocks. In the tissue culture studies on Citrus plants of C. grandis, C. sinensis, C. aurantifolia, C. karna and C. jambhiri were regenerated from different types of explants both of reproductive and vegetative origin. Retention of the regenerative potentiality by cultures of proliferating shoots of C. grandis and C. aurantifolia over a period of more than 13 years and 7 years respectively is yet another aspect of far reaching significance for germplasm preservation by the development of Tissue banks