臺灣農藥科學第四期電子書

82 臺灣農藥科學 第 4 期 Preliminary Study on the Effect of Fungicide on Pollen Viability Meng-Ni Shen 1 , Yeong-Jene Chiang 1* Abstract Shen, M. N., and Chiang, Y. J. 2018. Preliminary study on the effect of fungicide on pollen viabil- ity. Taiwan Pestic. Sci. 4: 69-82. In this study, the viability of cucumber pollen was used as a bioindicator to detect the phytotoxic effect of the fungicide hexaconazole on pollen germination, pollen tube elonga- tion, and dehydrogenase activity. In order to assess the phytotoxic effect, we performed a pollen viability assay, in which 50~150 cucumber pollen grains were incubated at 25 ℃ for one hour with 100 µL BK culture medium that contained 15% sucrose and technical or commercial formulation of hexaconazole. Results showed that both the technical and for- mulated hexaconazole were able to completely suppress pollen tube elongation and pollen germination; however, the degree of inhibition resulting from the formulated hexaconazole was much higher than that of the technical hexaconazole. Inhibitory concentrations of technical hexaconazole to reduce pollen tube length and pollen germination rate by 50% were 9.0 and 3.6 ppm, respectively, whereas the concentrations of formulated hexacona- zole required to achieve the same inhibition were 2.0 and 0.4 ppm, respectively. Indeed, experimental results of a dehydrogenase activity test (performed using a TTC assay) demonstrated that both pollen grain germination and pollen tube elongation were com- pletely inhibited when dehydrogenase activity was decreased to less than 40%. Finally, we found that cucumber pollen viability was significantly inhibited by hexaconazole, and that pollen tube elongation was more sensitive to hexaconazole than was pollen grain germina- tion . Key words: cucumber, pollen, pollen germination, pollen tube, hexaconazole, TTC staining method. Accepted: August 20, 2018. * Corresponding author, E-mail: cyj@tactri.gov.tw 1 Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Council of Agriculture, Taichung