Abstracts of the ASHS Northeast Region Annual Meeting

EFFECTS OF CARBON DIOXIDE ENRICHMENT AND IRRADIANCE ON EX VITRO ROOTING, ACCLIMATIZATION AND SUBSEQUENT GROWTH OF MICROPROPAGATED APPLE AND BLUEBERRY. Marvin Pritts and Dorcas Isuta*, Cornell University, Fruit and Vegetable Science Department. 134A Plant Science Building, Ithaca, NY 14850 Previous findings reveal that rooting and acclimatization of apple and blueberry plants is often difficult , inconsistent and inefficient. This experiment was set up in a fog chamber lo investigate the effects of CO 2 enrichment (CDE) and irradiance on unrooted stage II microshoots. Two CO 2 and 3 light levels tested were: 1350 +/150 (+ CDE), and 450 +/50 (CDE) ppm; 30 +/5 (low), 55 + 10 (medium), and 100 + 20 (high) umolm s -l respectively. Cultivars assessed were Berkeley and Northsky for blueberry. G65 and NY30 for apple. Blueberry microshoots acclimatized successfully and gave between 90 to 100% rooting and survival rate. Apple microshoots acclimatized and rooted slowly, exhibited great sensit ivity to in vivo conditions and gave between 40 to 100% rooting and survival rate. High light induced photo-inhibition which disappeared after complete acclimatization. There was a significant difference between low light and the other two light levels. The effect of CDE was dependent on cultivar. In most cases, high light (-) CDE gave the most vigorous growth (highest plant dry weight and leaf area). There was a significant difference between (+) CDE and (-) CDE at low and medium light, but none at high light. Low light (-) CDE and medium light (+) CDE were superior over low light (+) CDE and medium light (-) CDE. respectively. Stalling out in apple microshoots was corrected by GA3 sprays.