THE EFFECT OF SOIL DROUGHT ON GASES EXCHANGE IN THE LEAVES OF MAIZE (ZEA MAYS L.)

In greenhouse experiments, we have monitored the photosynthesis and transpiration rates in 15 genotypes of maize. Juvenile maize plants were cultivated in two versions of the experiment - a control version and a stressed version. The control plants were irrigated with 70 % of the field water capacity. For the stressed version, irrigation was completely discontinued for fourteen days. The experiment was started when five genuine leaves were grown. The lowest level of photosynthesis rate was in the stressed plants of the genotype 810*13 (4.28 mu mol CO2. m(2).s(-1)) and the highest level of photosynthesis rate was identified in the control group, specifically in the plants 2086 (11.58 mu mol CO2.m(-2).s(-1)). The provably lowest transpiration was identified in the genotype 2013: 0.76 mmol H2O.m(-2).s(-1), while the highest transpiration was identified in the genotype 23*704 (1.24 mmol H2O.m(-2).s(-1)). The genotype 810*13 responds sensitively to a drought-induced stress and the genotype CE704 seems to be tolerant to such conditions.