Reproduction of plants Plants Non- Flowering flowering By Flowers & Vegetative Spores Cones Seeds reproduction formation
Plant Asexual Reproduction Above ground Stems arch over and take root at the tips, forming new plants (Forsythia, Raspberry and Strawberry) Horizontal above ground stems are called stolons
Plant Asexual Reproduction Underground stems that serve for food storage and reproduction. Rhizomes, bulbs, corms and tubers
Plant Asexual Reproduction Leaves—Mitosis along the meristems at the leaf margins produce tiny plantlets that fall off and can take up an independent existence.
Advantages OfVegetative Propagation The young plant uses the food resources of the parent plant, while it is developing. Only one parent plant is involved. Good and desirable parental characters are retained in the offspring. The new plant formed matures more rapidly than the plant which grows from seeds. A large number of desired varieties of plant are produced in a very short time.
Disadvantages OfVegetative Propagation No new varieties are produced. Over crowding of the vegetative produced plants leads to severe competition for survival among them. Lack of variety leads to reduce resistance to disease and changes in the environment. Colonization of the new localities is unlikely. Thus the plants are not widely distributed.
The life cycle of aflowering plant 4. Pollination 3. Flower blossom 5. Fertilization 2. Plantdevelopment & maturation 6. Seed/Fruit formation 1. Germination 7. Seed dispersal
Seed Structure Seed coat / Testa Forms a tough Plumule protective layer Embryo shoot Embryo – grows into seedlingsCotyledon / Food storeProvides the embryo Radicleplant with food. Embryo root
Development of the seed and fruit There are many kinds of fruits Carpels Flower Stigma Stamen Ovule Carpel Each (fruitlet) Stigma segment develops Seed from the carpel of Stamen one flower Pea Raspberry PineappleSimple fruit - single carpel of Aggregate fruit - many separate Multiple fruit - many carpelsone flower carpels of one flower of many flowers
What are fruits like?The fruits can be: - soft & fleshy - hard & dry• What fruits can you think of?• What are their seeds like?
Seed Dispersal- why?Seeds must be carried away (dispersed /scattered) from the parent plant to:• Reduce overcrowding• Reduce competition for: - Water - Light - Nutrients
How birds and animals help seeddispersalBirds and animals eat the fruits and excrete the seeds away from the parent plant.
Development of the seed and fruit Fruits aid seed dispersalMany dry fruits are wind dispersed
Development of the seed and fruit Fruits aid seed dispersalSome dry fruits are animal dispersed
Development of the seed and fruit Fruits aid seed dispersalMany fleshy fruits are animal dispersed
Development of the seed and fruit Fruits aid seed dispersalSome fruits disperse seeds explosively (e.g., some mistletoes)
Development of the seed and fruit Fruits aid seed dispersalSome fruits make seeds buoyant, to aid dispersal by water
Seed DispersalDispersal Description Seeds/method Fruits Wind Seeds are designed to travel as far as possible. May have extensions which act as parachutes or wings. Fruits may be shaken like a pepper pot.
Seed Dispersal Dispersal Description Seeds/ method Fruits Animal Some have little hooks (external) or sticky substances so they stick onto the animal’s fur, are carried away and rubbed off later. Some carried away by animals and dropped.
Advantages of GM foods(1) Pesticide alternative Crop loss due to pests can be financiallycrippling for farmers which is the reason most farmers usepesticides. As an alternative to pesticides, crops such as corn andsoybeans can be genetically altered to resist pests - making thefarmer, the consumer and the environmentalist happy.(2) Disease resistance There are many diseases - includingfungi, viruses and bacteria - that can attack crops. With new GMtechnology, scientists can create crops that are genetically resistant tothese attackers.(3) Cold tolerance In order to prevent cold temperatures from killingcrops, scientists can take a gene that causes cold water fish to produce"antifreeze", and place it into certain plants that are susceptible tofrost.(4) Drought resistance Genetically altering crops to resist droughtand grow in otherwise non-ideal conditions (like poor soilquality), farmers are able to grow crops in areas that were previouslyunsuitable for agriculture.(5) Adding nutritional value Scientists are able to identifynutritional deficiencies in specific parts of the world, and geneticallyenhance the corn in order to satisfy the nutritional need.