ISHS Acta Horticulturae 531: II ISHS Conference on Fruit Production in the Tropics and Subtropics
ROOT-ZONE TEMPERATURE EFFECTS ON DRY MATTER DISTRIBUTION AND LEAF GAS EXCHANGE OF CAPE GOOSEBERRY (PHYSALIS PERUVIANA L.) |
| Authors: | G. Fischer, G. Ebert, P. Lüdders |
| Keywords: | Photosynthesis, transpiration, water use efficiency |
| Abstract:
In Colombia, cape gooseberries are grown on altitudinal sites (1800 to 2800 m a.s.l.) with a wide range of root-zone temperature (RZT). Dry matter (DM) distribution in different plant organs and net photosynthetic (Pn) and transpiration rate (T) as well as water use efficiency of photosynthesis (WUE) were investigated on ‘Colombia’ and ‘Kenia’ ecotypes under greenhouse conditions as dependent on three RZT: 14, 22 and 30°C. Generally, with rising RZT total DM production increased up to 22°C, but was higher in comparison to 30°C. DM allocation to roots showed no difference between 14 and 22°C, and was higher than at 30°C, suggesting that the high RZT could have resulted in a marked increase of carbon loss by root respiration. Fine root DM increased with declining RZT, whereas fruit DM increased constantly with rising RZT, because of enhanced DM concentration in fruits at higher RZT. Pn increased with RZT showing significant differences between 14 and 30°C, whereas T increased during the run of the experiment, reaching a maximum at 22°C RZT and a remarkable decline at the 30°C. Probably high air temperature (> 30°C) in combination with high RZT (30°C) and sand as substrate caused the decrease in T. WUE was enhanced markedly with rising RZT up to 30°C, probably due to an adaptation by cape gooseberries to high RZT, a frequent situation on the highland slopes of Colombia. | |
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