Effect of different moisture conditions on total chlorophyll content

--Gavrilescu, L, Bonea, D, Dobre, M, Paraschivu, M

Within the Southern Zone of Oltenia, only two years out of ten are favorable for the corn crop due to the higher temperatures and the lack of rainfall. Many other specialists in our country, as well as abroad (Morizet et al., 1990), have studied genetic and physiological drought tolerance (Terbea et al., 1994; Burzo et al., 1999).

This paper deals with the influence of plant density (40,000; 50,000; 60,000 plants/ha) and crop moisture conditions (irrigated and unirrigated) on the total chlorophyll content from leaves of 4 corn hybrids (F322, F376, Olt, Cocor). The experiment was performed at the Research Station of Simnic for three years. Climatically, 1999 was favorable for the corn crop, 2000 was extremely dry and 2001 was intermediate. Results are averages for the three years of the experiment.

Our results show:

(1) Highest total chlorophyll content was found for the irrigated plants (Figures 1-4).

(2) Regarding total chlorophyll content, the best results were given by the F376 (irrigated) hybrid, followed by Cocor.

(3) The best results for drought tolerance and total chlorophyll content combined were given by the F322 hybrid (unirrigated).

Figure 1. Total chlorophyll content for the F322 corn hybrid.

Figure 2. Total chlorophyll content for the F376 corn hybrid.

Figure 3. Total chlorophyll content for the Olt corn hybrid.

Figure 4. Total chlorophyll content for the Cocor corn hybrid.

The optimal density for the highest values of total chlorophyll in irrigated plants is between 50,000 and 60,000 plants/ha. In unirrigated plants, the maximum total chlorophyll was recorded for a density of 50,000 plants/ha. It was also observed that a density of 60,000 plants/ha caused a more intense shadowing of neighboring plants, resulting in the lower photosynthetic absorption emphasized in the graphics.