Effects Of Water Content On Growth, Physiological Characteristics, Yield, Fruit Quality And Water Use Efficiency Of Tomato Grown In Organic Substrate

95%(±5%), 80%(±5%), 65%(±5%), 50%(±5%) four relative water content treatments was designed in the experiment. Qifen, a tomato variety, planted self-made simple grooves and in organic substrate, had been used to study the effects of water content in organic substrate on the growth, physiological characteristics, yield, fruit quality and water use efficiency (WUE) of tomato grown in organic substrate. The main results were as follow: 1 With the water content increased in organic substrate, plant height, node length, stem thick, leaf area and rate of root and top of tomato grown in organic substrate evidently increased. When the water content in organic substrate was 80%, the plant appeared better and did not appear a deficit in water, and plant height, stem thick, leaf area, node length and rate of root and top were higher than others.2 With the water content increased in organic substrate, leaf chlorophyll content, net photosynthetic rate, transpiration rate, stomatal conductance of tomato grown in organic substrate also raised gradually but leaf water use efficiency descended. Contrast to the treatment of 50%, 65% and 95% relative water content in organic substrate, when tomato grew in 80% relative water content, leaf chlorophyll content, net photosynthetic rate, transpiration rates, stomatal conductance and water use efficiency were higher. When tomato grew in 50% relative water content in organic substrate, diurnal variation of photosynthetic rate took on a single-peak curve. Nevertheless, the diurnal variation of photosynthetic rate of 65%, 80% and 95% relative water content in organic substrate presented a double-peak curve.3 With the water content increased in organic substrate, leaf water potential (LWP), leaf osmotic potential (LOP) and root vigor of the tomato grown in organic substrate evidently increased by degrees. Contrast to the treatment of 50%, 65% and 95% relative water content in organic substrate, when the relative water content was 80% in organic substrate, leaf water potential (LWP), leaf osmotic potential (LOP) and root vigor of tomato grown in organic substrate was higher. And the plant was not wilting or expansive growth. And water potential of the first and second leaf in top could be regard as a physiological sign of water management.4 With the water content increased in organic substrate, the yield of tomato evidently increased. But the quality of fruit dropped distinctly (such as soluble sugar, organic acid, vitamin C, soluble protein, lycopene, ratio of sugar and aid). When the relative water content in organic substrate was 80%, yield and quality of fruit of tomato grown in organic substrate was higher. As the relative water content in organic substrate was 95%, the yield was highest, but the quality of fruit was worst. While the relative water content in organic substrate was 50%, the quality of fruit was best, but the yield was lowest. Nevertheless, the yield still came to 12855.4 kg/667m2.5 With the water content increased in organic substrate, economy water use efficiency (WUE) and biology water use efficiency (WUE) of tomato took on downtrend on the whole. Contrast to the relative water content 50%, 65% and 95%, when the relative water content in organic substrate was 80%, both economy and biology WUE of tomato were higher.6 When tomato would be planted in organic substrate, from the view of yields, fruit quality and water use efficiency, 80% relative water content in organic substrate could be taken as a quantitative index for water management of tomato grown in organic substrate. But only considered the highest fruit quality, 50% relative water content in organic substrate could be regarded as an index for water management of tomato grown in organic substrate.