TY - JOUR

T1 - Long term water stress inactivates Rubisco in subterranean clover

AU - Medrano, H.

AU - Parry, M. A J

AU - Socias, X.

AU - Lawlor, D. W.

PY - 1997/12/1

Y1 - 1997/12/1

N2 - In long-term field experiments, during consecutive years, microswards of subterranean clover were irrigated to minimise water deficits or subjected to progressively increasing drought over 30 days. Both leaf water potential and relative water content steadily decreased during the experiments. Plants affected by drought grew more slowly and photosynthesis was decreased. Photosynthetic rate (A) and Rubisco were analysed in relation to midday water potentials and relative water contents. The difference in A between droughted and irrigated plants increased progressively, in part as a result of decreased stomatal conductance and CO2 concentration within leaf (Ci). However, A-Ci curves suggest that the photosynthetic capacity in plants experiencing long-term stress was reduced by 50% when compared with irrigated plants. Drought decreased both the initial and the total Rubisco activity per unit area in a similar way but did not reduce the amount of Rubisco protein per unit leaf area. Thus, the specific activity of Rubisco, rather than its activation state, decreased suggesting that under water stress the active sites were blocked by inhibitors.

AB - In long-term field experiments, during consecutive years, microswards of subterranean clover were irrigated to minimise water deficits or subjected to progressively increasing drought over 30 days. Both leaf water potential and relative water content steadily decreased during the experiments. Plants affected by drought grew more slowly and photosynthesis was decreased. Photosynthetic rate (A) and Rubisco were analysed in relation to midday water potentials and relative water contents. The difference in A between droughted and irrigated plants increased progressively, in part as a result of decreased stomatal conductance and CO2 concentration within leaf (Ci). However, A-Ci curves suggest that the photosynthetic capacity in plants experiencing long-term stress was reduced by 50% when compared with irrigated plants. Drought decreased both the initial and the total Rubisco activity per unit area in a similar way but did not reduce the amount of Rubisco protein per unit leaf area. Thus, the specific activity of Rubisco, rather than its activation state, decreased suggesting that under water stress the active sites were blocked by inhibitors.

KW - CO assimilation rate

KW - Drought

KW - Leaf water potential

KW - Ribulose bisphosphate carboxylase

KW - Water stress

UR - http://www.scopus.com/inward/record.url?scp=0031416144&partnerID=8YFLogxK

U2 - 10.1111/j.1744-7348.1997.tb05176.x

DO - 10.1111/j.1744-7348.1997.tb05176.x

M3 - Journal article

AN - SCOPUS:0031416144

VL - 131

SP - 491

EP - 501

JO - Annals of Applied Biology

JF - Annals of Applied Biology

SN - 0003-4746

IS - 3

ER -