ISHS Acta Horticulturae 727: X International Symposium on Plant Bioregulators in Fruit Production
CONTROL OF PECAN SEEDLING GROWTH WITH A HEAT TREATMENT TO THE SEEDS |
| Authors: | M.A. Bustamante, J.A. Gonzalez, A. Benavides, L. Banuelos, A. Rojas |
| Keywords: | heat treatment, heat shock, growth inhibition, ABA, jasmonic acid, hormones |
| DOI: | 10.17660/ActaHortic.2006.727.7 |
| Abstract:
In previous experiments we were able to control the growth of pecan seedlings using synthetic growth retardants and naturally occurring phenolic compounds, but in this work we wanted to investigate if their growth could also be controlled by giving a heat treatment to the seeds. We subjected pecan seeds cv. Western to water soaking for 2 days, followed by a treatment at 2º and 30ºC for 10 days in a humid substrate, using a refrigerator and a seed germination chamber, respectively. The control received only the water soaking. After this 10-day period, we found that the seeds receiving the 30ºC treatment had sprouted, producing a root about 5 cm long, while the 2ºC seeds showed no sign of germination. After this treatment, the seeds were planted in a bed under greenhouse conditions to record their emergence and shoot length. We found that the 30ºC seeds emerged first, followed by the 2ºC seeds and then the control. This response continued for some time until we had 95% emergence in the two treatments, including the control. Because of the initial differences in seedling emergence, the length of shoots was greater in the 30ºC seeds, followed by the 2ºC and then the control; however, after some time, we found that the shoot growth of the 30ºC seeds slowed and then stopped while the shoots of both the 2ºC seeds and the control continued their normal growth, so that after a while the final shoot length of these seeds was higher than that of 30ºC seeds. We present some speculations which possibly indicate that ABA and Jasmonic acid may be involved in the growth inhibition induced by the heat treatment given to the seeds | |
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