A greenhouse pot experiment was conducted using a complete random design with six replications. A pressure-volume curve analysis was employed to study the effects of organic fertilizers on plant water relations in sweet corn (Zea mays L. cv.Honey-bantam) in terms of leaf osmotic concentration (CS), osmotic potentials at full turgid status (πFT) and at incipient plasmolysis (πIp), and of symplastic (ζsym) and apoplastic (ζapo) fractions in the tissue water compartment in relation to photosynthetic capacity (PC) and dry mass accumulation. At the seedling stage (day 15), plants with chemical fertilizer treatments showed lower πFT, πIp and ζapo and higher CS, ζsym and PC than those with organic fertilizer treatments.Compared to PC and relative growth, where values from day 15 to day 75 were first lower for organic treatments and then higher, ζsym and CS values were similar, while πFT and πip were opposite being higher then lower. Dry mass production with organic fertilizcr was higher than or close to the chemical fertilizer treatments in the later growth stage (day 75),though dry mass production with chemical fertilizers was much higher in the early and middle growing stages (days 15 and 45). Increased photosynthesis and dry mass production in later growth stages due to organic fertilizers were associated with increased osmotic concentration in the tissue and the symplastic fraction of the tissue water compartment. These might favor stomatal opening and biochemical activities.
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