Roots Primary Growth of Roots: Growth in Length A major part of the root is the root cap; the root cap is the covering on the end that protects the growing root. Cells in the root cap are aware of the direction of gravity and direct the root growth accordingly. As the root grows the outer cells of the root cap gradually get scraped off, as to be expected when growing in the rough soil …showed first 75 words of 1237 total…

…showed last 75 words of 1237 total…and thin cells arranged upright, perpendicular to the upper epidermis. Under the palisade layer is the spongy layer. The spongy layer allows gas to circulate to the photosynthetic cells in the leaf. Vascular tissue that runs through the layers in strands is called veins. The veins are important because they carry away products of photosynthesis and provides a supporting framework that stretches the delicate photosynthetic tissues where they can intercept sun rays and exchange gases.