Measuring Small Holes (IMAGE) Washington State University Caption Washington State University biologist Michael Knoblauch measured and counted thousands of microscopic holes to test an 86-year-old hypothesis of how nutrients are moved in a plant. Here he is with a microscope photo of a sieve plate that separates the elongated cells of a plant's vascular system. Credit Washington State University photo Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.