Effect of ZnO NPs Combined with Al2(SO4)3 and Sucrose on Inhibiting Microbial Growth in the Vase Solution and Improving the Quality of Cut Vanda Hybrid ‘Pure Wax Pink’

This study aimed to obtain the positive influence of ZnO NPs pulsing combined with aluminium sulfate (Al2(SO4)3) and sucrose (Suc) holding on inhibition of the microbial growth and improvement of the quality of cut Vanda hybrid ‘Pure Wax Pink’. Flower stems were pulsed with 0.25% ZnO NPs for 3 h, then transferred to 150 ppm Al2(SO4)3 + 2 % Suc at 21 + 2 °C. Throughout the experimental period, the qualities of pulsed flowers were determined for changes in relative fresh weight, water uptake rate, flower bud opening and inhibiting the growth of microorganisms in vase solution compared with untreated flowers holding in deionized water (DI) and Al2(SO4)3 + Suc as control. The result showed that ZnO NPs completely inhibited the microbial growth after pulsing and showed a minimum population of microbial in the vase on the other days as compared to the control. Although the control flowers holding in DI water and Al2(SO4)3 + Suc had higher percentage of fresh weight and floret opening as well as higher water uptake than that of ZnO NPs treatment, the combination between ZnO NPs pulsing and Al2(SO4)3 + Suc holding treatment significantly delayed floret senescence and extended the vase life to 14 days, whereas the control flowers holding in DI water and Al2(SO4)3 + Suc had 9.8 and 10.3 days, respectively.