Modification of pollen proteins induced by growth substances and fungicides

The present study investigated the effects of the fungicides benomyl, dodine and penconazole and the growth regulators CPPU and paclobutrazol on pollen germination and tube growth, the microtubular organization of pollen tubes and total pollen polypeptides in the apple cvs Golden Delicious and Red Delicious. Each chemical showed a specific effect in at least one of the assayed functions. The fungicides confirmed their inhibitory effect on pollen germinaton. The most marked effects were recorded in both cultivars for dodine and benomyl when applied at field rates; penconazole showed a stronger inhibition in Golden Delicious than in Red Delicious when applied at field rate. By contrast, the tested growth regulators exerted a slight promotion of pollen germination. CPPU seemed not to alter the microtubular organization in Golden Delicious when applied ar rates ranging from routine field concentration to as much as three times this dosage, while paclobutrazol induced an anomalous disposition of tubuline when applied ar triple the field rate. The three assayed fungicides produced polypeptide patterns in a different way when compared to their effect on pollen germination, The effects of these chemicals on pollen gene regulation needs to be elucidated as their mechanisms of action are in many cases still unknown.