Evapotranspiration and Mineral Content of Sedum kamtschaticum Fischer Under Saline Irrigation

• Published in: Communications in Soil Science and Plant Analysis 2017-07, Vol.48 (12), p.1399-1408
• Main Authors: Moritani, Shigeoki, Yamamoto, Tahei, Andry, Henintsoa, Saito, Hirotaka
• Format: Article
• Language: English
• Subjects: C3-CAM intermediate species; Carbon dioxide; Chemical composition; Chemical compounds; Crassulacean acid metabolism; Electrical conductivity; Electrical resistivity; Evaporation; Evapotranspiration; Green buildings; green roof; Green roofs; Greywater; Irrigation; Irrigation water; Leaves; Metabolism; Noon; Photosynthesis; Plant growth; Plant tissues; Potassium; Roofs; saline irrigation; Salinity; Salinity effects; Salts; Sedum kamtschaticum; Sodium; Soil; Tissue; Water resources; Water use; Water use efficiency
• ISSN: 0010-3624; 1532-2416; 1532-4133
• DOI: 10.1080/00103624.2017.1358743

An alternative water resource such as graywater could be used for irrigation on green roofs during hot, dry summers, although it contains salt. In this study, the response to high-salt stress of a C3-CAM (Crassulacean acid metabolism) intermediate species, Sedum kamtschaticum Fischer, was evaluated over a 2-month experiment in terms of evapotranspiration (ET) and chemical compounds in plant tissue in triplicate for both experiments. High ET (10-15 mm day −1 ) was observed under non-stressed conditions. On the day following the first saline irrigation, the peak ET at noon decreased as much as one-third of the maximum. After 9 days, ET remained below 3 mm day −1 , corresponding mostly to evaporation from the wet soil surface. The balance of chemical component contents in leaves changed depending on the electrical conductivity of irrigation water electrical conductivity (EC i ). The potassium to sodium (K + /Na + ) ratio, which indicates levels of sodium toxic for plant growth, decreased with higher EC i , while it excluded sodium from roots. However, based on enhanced water use efficiency under higher EC i regardless of reduced carbon dioxide (CO 2 ) assimilation under salinity stress, the plant's method of photosynthesis shifted from C3 to CAM metabolism. These findings show that S. kamtschaticum could survive for more than 2 months under low or moderate salinity of irrigation water in hot conditions.