| Titre : | Adaptation of corn zea mays l. kernel development to conditions of drought and thermal stress |
| Auteurs : | OUATTAR Said ; K Crookston |
| Type de document : | texte imprimé |
| Editeur : | (s.l) : (s.e), 1985 |
| Format : | 132 p. |
| Langues: | Anglais |
| Index. décimale : | F01 (L agriculture) |
| Mots-clés: | ZEA MAYS ; CROISSANCE ; STRESS |
| Résumé : |
In Mediterranean-type climates, rainfed maize frequently encounters intense water stress during grain filling. Little has been reported about the effect of water deficits during grain filling on the pattern of kernel development. The objective of this research was to determine the effect of short- and long-term water stress, imposed during different phases of grain filling, on the pattern of maize grain growth.
We conducted two separate experiments. In the first, the effect of a short-term (10-day) stress imposed during the lag phase (early) was compared with stress imposed during the linear filling phase (late). In the second, stress was initiated during the same phases but extended until maturity. Plants were grown outdoors in Rabat, Morocco, in large pots arranged to achieve a stand density of 50,000 plants ha⁻¹. Neither the early nor late short-term stress affected the calculated rate or duration of kernel growth. Short-term stress during the lag phase did result in a significant but transient delay in the accumulation of kernel dry mass. Recovery from this delay was such that there was no effect on the overall rate of kernel growth. However, short-term stress imposed during the linear-filling phase did not affect the pattern of grain filling. Only continuous stress treatments had a lasting effect on the pattern of kernel growth. When continuous stress was initiated during the lag phase, a normal rate of grain growth was maintained for 24 days. Grain filling then terminated prematurely, resulting in a significant reduction in the duration of the grain-filling period and a 50% reduction in final kernel mass. When continuous stress was not imposed until the linear-filling phase, grain filling continued at a normal rate for 20 days. It then also terminated abruptly, resulting in an eight-day reduction in the grain-filling period. This reduction was compensated by a slight increase in kernel growth rate; however, final kernel mass was not significantly reduced. Our results showed that kernel growth was more sensitive to water deficit during the lag than during the linear-filling phase of growth. The higher sensitivity of seed development to drought during the lag phase was not a consequence of either a lack of carbohydrate availability to the grain or an inhibition of starch synthesis. In fact, plants subjected to stress during the lag phase had more soluble sugars in the grain than did control plants. Our data suggest that the sensitivity of maize to drought during the lag phase may have been due to interference with endosperm cell division. |
| Directeur de thèse : | R.J. Summerfield |
| Membre du comité : | Kent R. Crookston/Hassan Chlyah/A. Fleury/Robert Jones |
| En ligne : | http://10.2.0.27/PDF_CDA/uploads/PDF/OUATTAR_Said_1985_1268.pdf |
Exemplaires (1)
| Code-barres | Cote | Support | Localisation | Section | Disponibilité |
|---|---|---|---|---|---|
| 100009847 | ES 15 | Support papier | Espace 1er étage | CEDoc | Consultation sur place Exclu du prêt |
