[Biochemical and physiological processes in maize related to drought tolerance] | Procesos bioquimicos-fisiologicos del maiz involucrados en la tolerancia a la sequia
1997
Raya P., J.C. | Pena-Valdivia, C.B. | Edmeades, G.O.
This work was done to determine whether the drought tolerance obtained in maize through recurrent selection is closely related to biochemical and physiological activities starting at early development stages. From the maize population, 'Tuxpeno Sequia', which underwent extensive selection for drought tolerance, seed of original population (C0) prior to selection and of C8 was grown in the greenhouse and submitted to drought beginning three weeks after emergence until permanent wilting occurred, at which point one irrigation was applied. Under drought, photosynthetic electron transport in situ was significantly reduced in C0 plants. In C8 plants, there was a reduction in photosynthetic pigments per unit dry weight and in variable and maximum chlorophyll fluorescence emissions (induced with 450 and 630 mmoles of photons/m2 s) in situ. Although relative water content was reduced 23 Per cent in C0 and 18 Per cent in C8 plants under early drought, as drought became severe differences between the experimental plants and the checks were nonsignificant. A similar result was observed for dry weight of tops and total root dry matter, which on average diminished 30 Per cent due to drought in plants from C0, a non-significant change. The 34 Per cent reduction in total dry weight of C0 plantlets was however significant. Drought also changed slightly the electrophoretic pattern of plants from both cycles. Drought and subsequent watering generally affected both maize populations equally, although it is possible that the traits measured do not adequately represent the effects of drought.
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