Abstract
Tomato (Fukuzyu No.2), eggplant (Hayabusa) and sweet pepper (Shinsakigakemidori) were grown in water culture under glasshouse condition in order to clarify the influence of concentrations of nutrient solution on their plant growth, exudation rate and chemical composition of xylem exudate.
1. Plants grown in standard solution had the greatest dry weight in each crop, followed by a decline with those supplied with lower or higher concentration of nutrient solution, with the degree of dry weight reduction in the following descending order: sweet pepper, eggplant and then tomato.
2. Exudation rate in each crop was similar to dry weight tendency, with a negative correlation between the concentration of nutrient solution and exudation rate.
3. An increase in the concentration of nutrient solution suppressed Ca absorption but promoted other minerals. It was shown that the levels of NO3-N, Ca and Mn in eggplant and P, K, Mg, Fe, Cu and Zn in sweet pepper were higher in comparison with the other crops, respectively. Tomato had lower levels of mineral elements in the xylem exudate than eggplant and sweet pepper, but it had the greatest amount of mineral absorption per plant per hour because of its high exudation rate.
