A quantitative study of water stress effect on sugarcane photosynthesis
| MSI07P4235 | |
| Koonjah, S S Walker, S Singels, A van Antwerpen, R Nayamuth, A R | |
| A quantitative study of water stress effect on sugarcane photosynthesis | |
| periodical article | |
| 2006 | |
| Proc. S. Afr. Sug. Technol. Assoc. | |
| 80: 148-158 | |
| En | |
| En | |
| Water scarcity is the most common limiting factor to sugarcane production in the tropics. With the on-going climate change the occurrence and duration of drought periods is expected to increase in the future. Water stress affects many processes linked to growth and development among which is photosynthesis. A better knowledge of such effects on cane and sugar production can be very useful if incorporated into models for yield prediction. In this context, a trial was established under a rainshelter facility at Mount Edgecombe with well watered and water stressed sugarcane variety NCo376. The rate of photosynthesis (PN), light interception (LI), plant extension rate (PER), leaf temperature (FT) and leaf water potential (YL) were measured together with the soil water content. Mild water stress affected PER followed by LI and PN. Difference in PN between the well-watered and water stressed cane could be observed when the YL of the latter reached -0.7 MPa. At this stage the PN which was at 20.0 µmolm-2s-1 started to decline reaching the lowest level of 2.2 µmolm-2s-1 at a YL of -1.6 MPa. A strong correlation was obtained when regressing PN with YL so that for every 0.1 MPa decrease in YL there was a linear reduction in PN of 1.6 µmolm-2s-1. The FT of the stressed cane was higher due to poorer cooling effect from higher stomatal resistance and accompanying reduction in transpiration rate. Regressing the values of PN against that of FT in the range of 25 to 40oC showed that PN in the stressed crop decreases linearly by 0.4 µmolm-2s-1 for every degree rise in temperature. The diurnal pattern of PN in well watered crop followed closely the daily trend of incoming solar radiation whereas in the stressed cane at -1.6 Mpa YL , PN was reduced to almost the zero level after midday. Hence, the photosynthetic efficiency of the stressed cane at -1.6 MPa was 0.22 per cent compared to 1.09 per cent for the unstressed crop. The lower biomass accumulation in the water stressed cane was attributed to reduced LI, PER and PN. | |
| sugarcane physiology photosynthesis water stress leaf water potential leaf temperature light interception | |
| Mauritius | |
| Sugarcane: Physiology | |
| Environmental stress | |
| 2007-01-28 | |
| En | |
| LIB | |
| Physiol |