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.
Yes, they do. During fertilization, the nucleus of the sperm and ova fuse to form a complete cell. Remember, the chromosome number in a sperm cell or ovum is half the normal n â¦ umber, or haploid.11 people found this useful.he sperm nucleus (in animals) contains the haploid chromosome set of the parent father. The egg or ovum carries the other half of the chromosome set from the parent mother. O â¦ n fertilisation the two sets fuse and a full set of chromosomes forms (diploid).