Ash, green, and red (Fraxinus spp.)âThe common. leaf spot and scorch on ash leaves is caused by the ash. anthracnose fungus, Gloeosporium aridum. Large areas of. infected leaves, especially along the edges, turn brown (Figure. 2). Premature leaf drop may occur.
How sperm and eggs develop precisely 23 chromosomes each. April 12, 2012. There are many tools that cells could use to separate DNA strands that cross over during meiosis. UC Davis researchers have identified the right tools for the job. Researchers at the University of California, Davis have discovered a key tool that helps sperm and eggs develop exactly 23 chromosomes each.
These are diploid cells. However, some cells, like the reproductive cells i,e sperm and ovum, contain 23 chromosomes, since they are to combine with other cells, sperm or ovum, at thw time of fertilization, which will make a normal human diploid cell. These are called haploid cells, which contain 23 chromosomes.