Abstract
Continuous and nondestructive measurement of plant growth in weight is considered to be one of the fundamental techniques used in studying mutual relations between plant growth and its environment. In the previous paper, a method of weighing growth of plant cultivated in water culture by the use of cantilever beam sensors was reported. In single cultivation, this method had some merits on measuring weight growth of a plant such as was not affected by changes of plant's posture, whereas in community state had demerits such as more channels for measurement and complicated operations were required.
In this paper, developing new measurement system of plant growth in community state was reported. The system was composed of two parts. The one was four load sensors and the other a loading plate. The former was the cantilever beam sensors developed in the previous paper and the latter, supported by the former above a water culture tank, was provided for the purpose of holding plants in community. The net weight of plant in community state could be measured by summing up the outputs of four load sensors and subtracting the weight of the loading plate.
By using these measurement systems and setting light condition showed in Fig. 7, an experiment was carried out for 35 days, in order to measure weight growth ofChrysanthemum coronariumin community state cultivated in water culture. The result was shown in Fig. 9 and the difference between weight measured by the loading plate and by a balance was about 1.5% of total plant weight in community state.
