Effect of antitranspirants on sunflower
Answers
: The experiment was conducted for two successive summer seasons 2016 and 2017 at Sakha Agricultural
Research Station, Kafr El-Sheikh, Egypt to evaluate the effect of foliar spray with antitranspiranrs under three levels
of soil moisture stress on growth, yield, yield components and water productivity of sunflower (Helianthus annuus
L.) cultivar Sakha 53. The experiment was laid out in a split plot design with four replicates. The main plots were
occupied by soil moisture levels namely wet (35-45%), medium (45-55%) and dry (55-65%) of maximum allowable
depletion of available soil moisture (MAD of ASW). While subplots contained three treatments of antitraspirants i.
e. without spray (control), spray with kaolin at 6% and spray with Magnesium Carbonate at 6%. Obtained results
proved that, increasing soil moisture stress up to (55-65% MAD of ASW) caused significant reduction in all growth
parameters, photosynthetic pigments (chlorophyll a, chlorophyll b), relative water content (RWC %) and seed oil %.
Also, yield parameters (stem diameter, head diameter, 100- seed weight and seed yield) show significant reduction
at dry treatment. On the other hand, increasing soil moisture stress caused significant increase in proline content and
seed protein % at both growing seasons. Foliar application with antitraspirants positively affected all the growth and
physiological criteria of the tested plants compared with control treatment and also cause marked reduction in
transpiration rate. Generally, under irrigation water shortage, application of antitranspirants effectively reduced
water consumption use and enhanced water productivity. Additionally, most of the growth and yield parameters and
seed quality were improved significantly as influenced by spraying antitranspirants which were responsible for
reducing water consumptive use.