The effect of dust on leaf chlorophyll, stomatal conductance and fruitset date palm trees (CV. Mozafati)

Dust nowadays has harmful effects on palm trees in different areas. This phenomenon has had a negative effects on the quantity and quality of the date crops. So effect of dust on leaf chlorophyll, stomatal conductance and fruit product percentage in date trees has been investigated.

The study regions were selected by using meteorological data with different dust concentrations. Routak (high dust intensity), Jalqh (medium dust intensity) and Saravan (low dust intensity) were selected. In each of the three regions, five groves and within each grove, 5 palm trees with similar conditions were selected. Leaf chlorophyll traits were measured in two modes without washing and after washing, As well as stomatal conductance of five chosen leaves.

The results showed a significant difference in leaf chlorophyll and stomatal conductance after washing. Saravan region with the least dust had the highest leaf chlorophyll and Routak with high dust concentration had the lowest chlorophyll. Also, the amount of chlorophyll in all three regions in leaf washing conditions was higher than the state of not washing the leaves. Chlorophyll in the region with high concentration of dust is much less than the area with less dust. The mean comparison results show a decrease in stomatal conductivity in areas with high dust concentrations (Routak area). The highest percentage of fruitset (92.98%) was obtained in Saravan region with less dust concentration. The most inferior fruitset (60%) was obtained in the Routak region with high dust concentration. The highest percentage of inoculation (98.85) and the lowest percentage of precipitation (1.14) were obtained in Saravan. The lowest rate of inoculation (89.28) and the highest percentage of shedding (10.17) were obtained in Routak region.

Dust settles on the leaves, closing the stomata, reducing the stomatal conductance and chlorophyll. Severe dust reduces fruitset, fruit formation percentage and increases fruit drop percentage. In general, the obtained results showed the adverse effects of high dust concentration on the studied traits.