Genetic modifications of canopy structure may result in enhanced yield when water is a limiting factor. Three near-isogenic pea genotypes carrying genes which determine a striking effect on leaf morphology were grown in lysimeters under two extreme water regimes. Pea genotypes of normal and reduced leaf and stipule morphology were cultivated at a plant density of 72 m−2 in drainage lysimeters, where a well watered regime was established by irrigating whenever tensiometric values reached (0.05 MPa). After 70 days from emergence, a second regime was created by withholding water until wilting symptoms were visible; the control plants were irrigated 12 times, whereas the stressed plants only once. Dramatic differences in dry matter accumulation were found between the two irrigation regimes. The physiological response varied accordingly. Under stressed conditions, genotype af, which has the leaflets transformed into tendrils, showed a faster CO2 exchange rate (CER), a lower stomatal resistance, and a lower canopy temperature than the other two genotypes. This allowed a reduced soil water consumption, but a higher pod dry matter accumulation, which doubled in the last 2 weeks. This behaviour was also favoured by a leaf dry matter accumulation, in terms of quantity and duration, significantly higher than that shown by the other two genotypes. Additionally, af plants showed a higher leaf/stem ratio and negligible senescence.
Response to low soil water potential in pea genotypes (Pisum sativum L.) with different leaf morphology
LEONE, ANTONIETTA
1993-01-01
Abstract
Genetic modifications of canopy structure may result in enhanced yield when water is a limiting factor. Three near-isogenic pea genotypes carrying genes which determine a striking effect on leaf morphology were grown in lysimeters under two extreme water regimes. Pea genotypes of normal and reduced leaf and stipule morphology were cultivated at a plant density of 72 m−2 in drainage lysimeters, where a well watered regime was established by irrigating whenever tensiometric values reached (0.05 MPa). After 70 days from emergence, a second regime was created by withholding water until wilting symptoms were visible; the control plants were irrigated 12 times, whereas the stressed plants only once. Dramatic differences in dry matter accumulation were found between the two irrigation regimes. The physiological response varied accordingly. Under stressed conditions, genotype af, which has the leaflets transformed into tendrils, showed a faster CO2 exchange rate (CER), a lower stomatal resistance, and a lower canopy temperature than the other two genotypes. This allowed a reduced soil water consumption, but a higher pod dry matter accumulation, which doubled in the last 2 weeks. This behaviour was also favoured by a leaf dry matter accumulation, in terms of quantity and duration, significantly higher than that shown by the other two genotypes. Additionally, af plants showed a higher leaf/stem ratio and negligible senescence.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
