File:52. Сложени скробни зрна од ориз (Oryza sativa).ogg

English: Complex starch grains of Asian rice (Oryza sativa) under microscope

During the process of photosynthesis in plants, sugars are created in the form of starch. Those sugars are stored in the leukoplasts in the cells and form starch grains. We use flour from ground rice grains to prepare this slide. Two drops of water are placed on the object glass, one central larger and one peripheral smaller. With the back of the tweezers, pick up the powder mass and pour a small amount onto the middle drop of water. The excess of the powdered mass is returned back to the container. A cover glass is placed on it, which is lowered next to the peripheral drop of water and at an angle of 45° it moves towards the middle of the object glass until the moment when the two drops of water merge, during which it is lowered. This procedure needs to be performed precisely because otherwise air bubbles will form which will count during microscopy. We add water under the cover glass in order to push out the trapped air. In this way, the native microscopic slide is prepared and it is ready for microscopy. Complex starch grains are built from a large number of simple starch grains, under mechanical influences the complex grain can break down into a large number of simple grains.

Prepared and performed by Sara Cvetanoska, Institute of Biology, FNSM, Ss. Cyril and Methodius University, Skopje, Macedonia.