Effect of Foliar Application of Zinc and Benzyladenine on Growth, Yield and Chemical Constituents of Tuberose Plants

This study was conducted in Oseim district, Giza governorate, during the two successive seasons of 2007 and 2008, to investigate the effect of zinc sulphate and benzyladenine foliar application on the flowers, yield and some chemical constituents of Polianthes tuberosa L. plants. The soil of the experiments was clay loam in texture, tented to alkalinity in reaction and had low content of zinc. Plants were sprayed three times with Benzyladenine (BA) (N-6-benzylaminoacid at (25, 50 and 100 ppm) and zinc sulphate at (0.75, 1.50 and 3 g/l). All studied parameters of flowering characteristics, number of bulblets/plant and fresh weight of bulbet and bulblet / plant were significantly increased by foliar spraying of zinc (Zn) or benzyladenine (BA), at all investigated rates over the control. The increase of Zn or BA rates from the lower to the middle rates significantly increased all floral characters and further increments of either Zn or BA rates had no significant effect or declined some of the investigated flowering traits and bulbets yield. The interaction between Zn and BA had significant effect on flowering and bulbs characteristics of tuberose. Zn foliar application significantly increased N, P, K, Fe, Mn, Zn and Cu content in plant organs, with the exception of K in flowers and P in bulbs also. Total carbohydrate contents of different tuberose plant organs and flowers oil percentage were significantly increased with Zn and or BA foliar spraying. The highest total carbohydrates content of different plant organs and flowers oil percentage resulted from the combination of 3.0g Zn/l with 100 ppm BA, and 1.5g Zn/l with 50 ppm BA, respectively. Component of essential oil of tuberose was analysed.