Plants for Food and Fibre – Unit 2 (Science in Action 7) PDF

Learning Pack for Plants for Food and Fibre – Unit 2 (Science In Action 7) 6 Pollination Pollination can occur by self-pollination or cross-pollination. Pollination occurs after a pollen grain lands on the stigma of the flower, above the ovary. The pollen grain produces a pollen...

Learning Pack for Plants for Food and Fibre – Unit 2 (Science In Action 7) 6 Pollination Pollination can occur by self-pollination or cross-pollination. Pollination occurs after a pollen grain lands on the stigma of the flower, above the ovary. The pollen grain produces a pollen tube that grows down from the stigma to the ovule. Through this tube, cells transfer from the pollen grain to the ovule. The ovule then grows into a seed. Pollination visual description at: http://www.botany.uwc.ac.za/ecotree/flowers/pollination.htm Pollinators Dispersal is the transportation of seeds away from the parent plant. It can happen in various ways, including: wind, waterways (rivers, streams, etc.), bird droppings , animal fur, and fire. Farmers use machines to disperse seeds. Once they have grown into the crop, they are harvested in two steps. A swather cuts the plants and lays them in rows (the stubble - what is left of the plant after being cut - prevents the plant from touching the soil, so the seeds can ripen). A combine then separates the grain from the rest of the plant. (The grain seeds are collected and the straw is baled, or spread evenly over the field). The bee spreads pollen over more crops than any other insect. Artificial pollination can also be used to breed different varieties of plants for specific purposes (usually to produce a better yield, or one that is more resistant to environmental conditions - such as cold winters) It is not just exposure to cold temperatures that kills seeds, but prolonged exposure to cold temperatures. Cones The cone is the part of the tree that has a series of woody scales, and come in various shapes and sizes. Both male and female cones are produced by cone-bearing trees. Female cones contain ovules (eggs) - the small bumps at the end of a scale in a cone. Pollen grains (containing sperm) develop on the smaller male cone. Wind carries the pollen grains to the female cones. Although most of the pollen grains never reach the female cones, those that do get caught in the sticky fluid near the ovule. A pollen tube grows to the ovule and sperm is able to fertilize the egg. The process of pollination is complete. Female cones of pine trees mature, open, and release their seeds during the fall or winter months. (This whole process takes at least two years) The seeds can then be dispersed by various methods and when they get covered they can eventually sprout and become new pine trees. Reproduction Without Seeds Asexual, or vegetative reproduction, occurs when a 'parent' plant grows new plants from its roots, stems, or leaves. Plants that reproduce by vegetative reproduction are genetically identical to the parent that produces it. Some plants reproduce from stems: Strawberry Runners Gladioli Corm Cattails Horizontal Cacti Flattened layering (runners) fragmentation (buds and Rhizomes Stems root systems) Plants can also reproduce from their roots and are called suckers. Technology to Reproduce Plants Asexual reproductive technologies include: cuttings – small pieces of a plant that usually have part of the stem and a few leaves. grafting – one stem cutting that is attached to the stem of another plant, eventually growing together. Copyright 2005 – Developed by Edquest Resources (www.edquest.ca)