The Pattern of Stomatal Opening through the Exposure of High-Frequency Sound Wave with the Different Duration and Age of Soybeans (Glycine max (L.) Merril)

Abstract

Since the productivity of soybean in Indonesia is still low, a new innovation is needed to improve it. The objectives of this study are to determine a pattem of the stomatal opening of soybean's leaves which exposed by high-frequency sound waves with different duration time and age of soybean plants. This study was carried out at the Experimental Farm Agriculture Faculty and Biology Laboratory of Science Faculty of the Islamic University of Malang, East Java in April to August 2013.The first factor was duration time of the exposure which consist ofthree levels: 20 minutes (D1), 40 minutes (D2) and 60 minute (D3).The second factor was the age of the soybean which consist of three levels: l5 days after planting (dap) (At),25 dap (Ar) and 35 dap (A3). The soybean plants were exposure by the 5000 hertz frequency. The variables measured consisted of stomatal opening width, plant height, leaf area, fresh weight of pods, fresh weight of seed, oven dry weight of beans and harvest index. Increase of the duration time of exposure of high frequency sound waves by 20 to 60 minutes, tends to decrease the width of stomatal opening. The treatment of duration of exposure by 40 minutes at the age of l5 dap had the highest soybean grain yield by 24.10 g.planfr, equivalent to 3.93 ton.hal. The relationship between the widths of the stomatal opining wiihsoybean production showed no significant correlation. The results of this study suggest that maintaining stomatal opening at optimum width through the manipulation of high-frequency sound waves will increase the yield of soybean plants. Keywords: soybean, high frequency sound waves, stomatal width, duration exposure, the age of application 1. Introduction Soybean (Glycine max (L.) Menil) is one of the important agricultural commodities in addition to rice and com. Soybean is the main source of vegetable protein and oils of the world as well asin Indonesia. However, 70o/o of soybean needs of Indonesia are still met from imports. It means the domestic soybean needs can only meet 30%. Soybean productivity of Indonesia in the last 10 years has reached 1.27 ton ha-r. The productivity is still low when compared with the soybean-producing countries such as Japan and China (Antara, 2008). Therefore, the efforts to improve the productivity is greatly needed. The various soybean cultivation technology has been applied to improve productivity such as the use of high yielding varieties, a balance fertilization, integrated pest and