| Regulating effect of fertilization form on gas exchange in leaves of sweet potato under different soil water conditions |
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| DOI：10.7606/j.issn.1000-7601.2009.04.20 |
| Key Words: sweet potato soil water fertilization form gas exchange regulation |
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| Abstract: |
| To understand the regulating effects of soil water and fertilization on gas exchange in sweet potato leaves under different condit
ions of soil water, with two cultivars of Qinshu 4 and 619 as materials, a pot experiment was conducted to measure and assay photosynthesis rate(Pn), water
use efficiency(WUE), transpiration rate(Tr), stomatal conductance(Gs), intercellular CO2 concentration（Ci） and stomatal limitation value(Ls). The results showed that soil water and fertilization significantly influence Pn, Tr, WUE, Gs and Ls. An apparent interaction existed between soil water and fertilization. Compared to the soil water content of 70%～75%，the changes of Pn, Tr, WUE, Gs and Ls were smaller under the soil water of 40%～45%, while under the soil water of 30%～35%, Pn, Tr, WUE, Gs and Ls, decreased significantly but Ci increased remarkably. Fertilization could enhance Pn, Tr, WUE, Gs and Ls, but reduce Ci. The regulating effect of these indexes with combined application of nitrogen and phosphorus was better than that with single application of nitrogen. The change of Ci and Ls under different treatments showed the gas exchange of sweet potato leaves was mainly limited by stomatal factors under the soil water of 40%～45%, and was mainly limited by non-stomatal factors. Fertilization could promote the gas exchange of sweet potato leaves by enhancing the effect of stomatal factors. |
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