Kingdom Plantae Nutrition
Photosynthesis- • The process of converting solar energy to chemical energy • Used by green plants, algae, euglena, and the blue-green bacteria • 6 CO2 + 6 H2O -------------> C6H12O6 + 6 O2 Carbon Water Glucose Oxygen dioxide
How we perceive color • Sunlight is a mixture of all visible wavelengths • Objects appear a certain color because they are reflecting that wavelength • So when we look at green plants, red and blue light is absorbed (used for photosynthesis) and green light is reflected
The visible spectrum • Light travels in particles that form waves • The shorter the wavelength the greater the available energy • Violet=the greatest energy • Red=the lowest energy
Pigments-substances that absorb light • Photosynthetic pigments • 1) chlorophyll a-primary photosynthetic pigment • 2) chlorophyll b • 3) carotenes-reflect orange light • 4) xanthophylls-reflect yellow light
Chlorophyll a hides the other pigments • It is the first to break down in the fall when sunlight decreases and temperatures cool • This is why we see other colors in the fall
Chloroplasts-cell organelle containing photosynthetic membranes and pigments • Thylakoids-”green disks”, the photosynthetic membranes inside • Grana-stacks of thylakoids • Stroma-regions around the grana Stroma Thylakoids
Photosynthesis- • The process by which organic compounds (glucose) are synthesized in the presence of carbon dioxide and light
Factors affecting photosynthesis • 1) light intensity-as intensity increases, rate of photosynthesis increases (to a certain point) • 2) water-a deficiency will slow or stop photosynthesis • 3) minerals, carbon dioxide, nutrients-a deficiency will slow or stop photosynthesis • 4) temperature-this influences enzyme activity
Heterotrophic plants • Mistletoe-a parasitic plant • It photosynthesizes but also takes sap from the vascular tissue of host plants such as oaks
Heterotrophic plants con’t • Indian pipes-does not photosynthesize • Lives symbiotically with a fungus
Heterotrophic plants con’t • Pitcher plants-photosynthetic but supplements missing nutrients in its environment with nitrogen from captured insects • Venus flytrap does this too!
Plant Regulation • Remember the factors that affect photosynthesis? • Plants need to regulate carbon dioxide intake and water loss • Leaves have pores called stomata that let carbon dioxide in and oxygen out
Stomata • If stomata are open, what is lost along with oxygen? • Water!!!! • So plants close stomata during times of high water loss (like hot, sunny days)
Guard cells • The cells surrounding the pores or stomata of a leaf are called guard cells. • In the photo, the dark center is the stomate and the cells surrounding it are the guard cells.