GROWTH OF ISOLATED SHOOT APICES OF TOMATO ON CALCIUM-DEFICIENT MEDIA AS RELATED TO LIGHT QUALITY DURING FOR INITIAL SEEDLING GROWTH

Apical shoot meristems were isolated from 20-day-old tomato (Lycopersicon esculentum Mill.) seedlings grown in white (WL), red (RL), or green (GL) light. The meristems were cultured in WL for 21 days on the nutrient media defined for stem morphogenesis: full Murashige-Skoog (MS) medium (the control), the MS medium deprived of CaCl2(-Ca), or the MS supplemented with 2 muM EGTA (-Ca + EGTA). The extent of shoot development from the apical meristems cultured on the control medium (stem and root length and the number of leaves) was shown to depend on the light quality applied during the initial seedling growth. On the (-Ca) medium, all the shoots derived from the meristem of WL-grown seedlings produced stems with dead apices and other developmental abnormalities; half of the shoots that originated from the meristems of RL-seedlings lost the ability for apical growth, and only in 22% of the explants from GL-seedlings stem apices die off. On the (-Ca + EGTA) medium, the meristem of WL-seedlings expanded and produced callus, the RL-explants formed teratic leaf-like structures, and the GL-explants died without visible growth. It is suggested that the quality of light used for seedling growth differentially affected the calcium distribution in apical meristematic tissues.