Growth Stages of a Rice Plant
Introduction: The rice plant has tillers which are a characteristic of grass plants; however they have recognized a way of growing the plant which causes it to create the best grain possible. Discussion: Vegetative: In this stage the plant germinates and gradually grows taller and leaves emerge at steady intervals. Germination: The root elongates through the seed coat and anchors into the soil. The primary leaf (coleoptile) also elongates and breaks through the seed coat. Early seedling growth: The first internode (mesocotyl) elongates and pushes the coleoptile through the soil.
The seminal and secondary roots continue to develop, and the first four leaves appear. Stem development: Tillering starts after the fifth leaf emerges. Tillers are the visible segments on the stem of the rice plant. Each tiller holds a two-part leaf. This tiller emerges from the auxiliary bud on the second leaf. The next tiller emerges on the third leaf after the sixth leaf emerges. This growth continues with the tiller emerging on the (n-3) th leaf after the nth leaf emerges until the maximum tiller number is reached.
The secondary roots continue to grow down until they flood the plants and then the roots grow both vertically and horizontally. Once the plant has reached the maximum tiller number it enters a vegetative lag phase where the height and diameter of the stem still increase, but not as fast, and the tillers start to decrease in number. Reproductive: Many things happen in this stage: the stem continues to grow taller, the tiller number continues to decrease, booting, the emergence of a flag leaf, heading, and flowering.
Increased plant growth: The plant undergoes PI (Panicle Initiation) where the panicle grows up the main stem of the rice plant as the plant continues to grow. Emergence of flag leaf (last leaf): The last leaf swells as the panicle grows up the flag leaf. This is where meiosis occurs in the plant (asexual reproduction), scientist call it booting. The panicle then emerges from the flag leaf (heading). Flowering: The outside parts of the panicle, the lemma and palea, open and close for one to two hours. The panicle stretches out their stamens which have pollen on them while their stigma gathers pollen from the air.
Fertilization: The fertilization of the ovary from the pollen creates the brown rice. The size and weight of the grain continues to increase as the stem and leaves transfer the sugars and starches they had collected. The grain changes from a green color to a gold color and the leaves of the rice plant start to die. The amount of light is important in this step because the most of the carbohydrates needed for the grain to grow come from photosynthesis in this step. Ripening (maturity phase): There are four stages to the ripening process.
The first is the milk stage, in this stage the starch grains of the kernel are soft and the inside of the kernel is filled with a white milky liquid. The second stage of the ripening process is the soft dough stage where the inside of the kernel is still soft, but it is becoming more firm. The third stage of the ripening process is the hard dough stage where the kernel is firm, but the moisture is still too high for harvest. The final stage of the ripening process is the maturity stage where the moisture is low enough and the kernel is firm enough to harvest the rice plant.
Conclusion: The first stage of plant development is the developmental stage which is split into three categories: germination, early seedling growth, and stem development. The second stage is the reproduction stage which is split into five categories: increased plant growth, emergence of flag leaf, flowering, and fertilization. The last stage is the ripening stage. Reference List Moldenhauer, K, Slaton, N. (2000) Rice Growth and Development. In Rice Production HANDBOOK. (Chapter 1, pg. 7-14) from http://www. uaex. edu/Other_Areas/publications/PDF/MP192/MP192. pdf
