XVI International Botanical Congess

Following the discovery in our laboratory of salicylates effects on the physiology stomata, since 1978 (Physiol. Plant., 43:126-128) we now report the positive effect of salicylic acid (SA) sprayed in shoots on root growth of wheat seedlings. Seeds of wheat cv. Nacozari were sown in pots with vermiculite under greenhouse conditions. When the seedlings were 12 days-old, were sprayed with SA at concentration of 10-8, 10-7, 10-6, 10-5 and 10-4M, and one treatment was sprayed with water as control. After 7 days of SA application, the seedling were harvested, and determined root length, root fresh weight, shoot fresh weight, and cell size in root tip. SA 10-8 and 10-7M showed the highest significant values of root length (31.8 and 31.3 cm) in comparison with the control treatment (26.5 cm), it means an increase of 20 and 18% respectively. Root fresh weight also was increased by SA 10-8M (0.37 g), an increase of 23% of root growth occurred respected to the control, shoot fresh weight was not affected by SA. The size of the cells from the root tip in the control were bigger than the cells of the treatments with SA. There was a clear effect of SA on the length of cells of the root tip. Further work with other plant species showed that the effect was reproducible. The implications of this discovery for agriculture will be mentioned..