They consist of rapid-growing, relatively undifferentiated cells D. Lengthwise growth produced by apical meristems is called primary growth 1. The tip of the root is called the root cap a. The root cap pushes through the soil b. A micrograph of a growing shoot is pictured in fig. A. An increase in the girth of a plant results from secondary growth 1.
Secondary growth occurs due to cell divisions in the vascular cambium a.
In the temperate zone, the strong seasonal growth activity creates growth rings in a tree 1. This causes rings of different thickness to develop i. Development of pollen and ovules in the angiosperms A. Remember that the body of an angiosperm is called the sporophyte 1. The sporophyte produces the egg and pollen in the anthers and ovules 1. At fertilization, the male and female gametes unite, forming a diploid zygote 1.