The effects of pesticides on morphology, viability, and germination of Blackberry (Rubus glaucus Benth.) and Tree tomato (Solanum betaceum Cav.) pollen grains

Abstract

The objective of this study was to determine the effect of application of pesticides on morphology, viability, and germination of pollen grains of Blackberry (Rubus glaucus Benth.) and Tree tomato (Solanum betaceum Cav.). The study was performed at Patate, Tungurahua province, Ecuador and was divided into two phases. Phase one dedicated to the study of morphology, viability, and identification of nutrient solution for better germination of pollen grains and phase two for the analysis of the effect of conventional, organic, and biological pesticides on pollen grain germination and pollen tube length. To study pollen morphology, pollens were extracted by hand pressure and was analyzed by optical and electron microscopy. The viable pollen grains were identified by staining with 1% acetocarmine. Even though Tree tomato and Blackberry pollen grains are morphologically similar, their exine shapes differ. We observed four times increase in pollen germination rate when suspended in nutrient solution (Sucrose with Boric acid) than control (water). Pollen grains under nutrient solution were subjected to different groups of pesticides for the period of 2, 4, and 6 h. With respect to pesticide affect, the Blackberry pollen grain germination followed the following order: Lecaniceb > Beauveb > Metazeb => Myceb > Control. However, the effect on Tree tomato pollen grains was as follows: Lecaniceb > Myceb > Cantus > Bacillus thuringiensis > Kripton > Control. As per as pollen grain germination is concerned, we observed that the chemical pesticides are more harmful than other pesticides. So, it is necessary to perform screening test for different pesticides and their effect on pollen grain germination before applying to the fields.