ABSTRACT
The objective of this study was to evaluate the effect of Ca and Mg silicate and B on the gas exchange, leaf water potential and chlorophyll fluorescence parameters in the sunflower variety Embrapa 122 -V2000 under water stress conditions. The trial was conducted in Red Yellow Latosol with very clayey texture, with contrasting levels of Si and B and subjected to water deficit. The experimental design was randomized blocks in a 24 factorial arrangement, with five replicates. Treatments consisted of the combination of two acidity corrective agents (calcium magnesium silicate and dolomitic limestone), two levels of base saturation (30 and 70%), two levels of B (0.18 mg dm-3 - value available in the soil and 1.20 mg dm-3) and two water regimes (with and without water stress from the beginning of flowering). It can be concluded that the supply of Si and B can reduce the damage to sunflower caused by water stress.
Key words:
Helianthus annuus; chlorophyll fluorescence; gas exchange; leaf water potential
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Same letters between two water regimes of each period do not differ statistically by Tukey test at 0.05 probability level. Bars of error represent the standard deviation of the mean of five replicates
Same uppercase letters between the two water regimes do not differ statistically by Tukey test t 0.05 probability level. Bars of errors represent the standard deviation of the mean of five replicates
Means of photosynthetic rate and stomatal conductance of each period after water deficit application were compared based on least significant difference (LSD)
Means of photochemical quenching coefficient of each period after water deficit application were compared based on least significant difference (LSD)