A cropped soil column system was used to analyze water and ion dynamics in soil affected by root absorptive functions of different crop species. The respective soil columns were cropped with corn, sunflowers, beets, and frog-fruits (i.e. cover grass), where the salinized groundwater was supplied as found in the salinized crop fields under desertification. In the corn and sunflower columns, the increased transpiration of leaves and decreased Na⁺ and Cl^- absorbing Power of roots resulted in increased salt accumulation in the soil, while the major essential ions of NO₃^-, PO₄^3- and K⁺ were actively absorbed by roots and scarcely remained in the soil. In the beet and frog-fruit columns, it was considered that transpiration was low compared with the corn and sunflower columns and also soil surface evaporation was depressed by leaves growing horizontally over the soil surface. Furthermore, beet roots showed uniquely high Na⁺ and Cl^- absorbing power. These factors resulted in decreased salt accumulation in the soil of the beet and frog-fruit columns. The lowest salt accumulation occurred in the no-crop column (without leaf transpiration and root absorptive functions). These results demonstrated that the transpiration, active and selective ion absorption, and leaf morphology of different plant species have a large influence on the amount and composition of ions accumulated in the soil.

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The hourly CO₂ assimilation rate of lettuce plants (A) in a closed system with artificial lighting (CSAL) for commercial production was estimated based on the CO₂ balance. Constant values for workers' respiration rate and number of air exchanges per hour were used to simplify the estimation. A was varied during the experimental period due to the variation in the leaf area of lettuce plants under lighting (LAL). However, the estimates of A contain inaccuracies. The percent error in A due to the variation in number of air exchange per hour can range from - 8 % to 20 %. Besides, the variation in the workers' respiration rate also can cause inaccuracy of A. The results indicate that A can be estimated based on the CO₂ balance. The number of air exchanges per hour and estimation of workers' respiration rate must be accurate to improve the accuracy of A.

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We investigated the effect of forcing temperature on the blooming of cut branches of an ornamental peach, Prunus persica (L.) Batsch ‘Yaguchi.’ Cut branches were concurrently kept in temperature-controlled glasshouses with daily minimum temperature of 5, 10, 15, 20 or 25°C subject to natural day length. Progressively earlier blooming dates were observed as minimum daily temperature increased, but higher temperatures were associated with reduced flower size and less vivid flower color. The optimum range of forcing temperature for flowering in cut branches of ‘Yaguchi’ was 15 to 20°C.

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