Abstract:

In this study, the method of silicon content determination in Cucurbitaceae crop tissues was modified aiming to provide technical support for the application of silicon fertilizer and related researches in horticultural plants. Different Cucurbitaceae crops including cucumber (Jinyou No.1), pumpkin (Miben) and watermelon (Zaojia 8424) were used in this study, and the effects of grinding temperature, grinding time, extracting time, water bathing time, reduction reaction time and absorption wavelength on the determination of silicon contents were investigated. As for silicon extraction process, measured value of silicon content by grinding under low-temperature (liquid nitrogen,-196 ℃) showed significant higher than that under room temperature. The results of the orthogonal test and full factorial experiments showed that the combination of low temperature grinding at 50 Hz for 30 s and extracting for 10 min was the best assay. The measured value tended to be stable after 3 min of water bathing, 2 min of reduction reaction. In addition, the results showed that the maximum absorption of silicon molybdenum blue was 810 nm. In conclusion, the optimal methods for silicon extraction and determination were as follows: 50 Hz grinding at low-temperature (liquid nitrogen,-196 ℃) for 30 s, extracting for 10 min at room temperature, 50 ℃ water bathing for 3 min, reduction reaction for 2 min, and the absorbance value was determined at 810 nm using spectrophotometer. The recovery rate of this method was 93%-108%.

Key words: silicon molybdenum blue, Cucurbitaceae, leaf, silicon, grinding temperature, extracting time, wavelength