Effects of CO2 enrichment on stock plant growth, cutting yield, and quality in Kalanchoe blossfeldiana.

摘要

This study was conducted to determine the effects of CO2 on stock plant growth and cutting production in Kalanchoe blossfeldiana. 'Margrethe'. Stock plants were grown at ambient (450+or-50 micro mol mol-1) and elevated (850+or-50 micro mol mol-1) CO2 levels. CO2 assimilation rate increased with sunrise and decreased with sunset according to light intensity change pattern, whereas CO2 gas exchange showed the opposite pattern. However, temperature did not greatly influence CO2 assimilation rate, which was highest at 400 micro mol m-2 s-1 photosynthetically active radiation (PAR) at 20 degrees C, and 300-400 micro mol m-2 s-1 PAR at 25 and 30 degrees C. In addition, the highest CO2 assimilation rate was recorded with 1200 micro mol mol-1 CO2 at 25 degrees C and 400 micro mol m-2 s-1 PAR. With 800 micro mol mol-1 CO2, the CO2 assimilation rate was 70-80% of that with 1200 micro mol mol-1 CO2. Elevated CO2 promoted stock plant growth, the number of cuttings, and cutting quality. Cuttings harvested from CO2-enriched stock plant resulted in promoted rooting and growth after 21 days of growth. This resulted from the accumulation of carbohydrates by increase in photosynthesis under high CO2. Elevated CO2 reduced stomatal conductance and transpiration of stock plant, and thereby inhibited mineral nutrient uptake. In conclusion, CO2 enrichment could be recommended to improve stock plant growth and cutting yield and quality in 'Margrethe' kalanchoe..