* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Basic Principle in Plant Physiology
Survey
Document related concepts
Cell membrane wikipedia , lookup
Signal transduction wikipedia , lookup
Tissue engineering wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Cell growth wikipedia , lookup
Cytokinesis wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cell culture wikipedia , lookup
Cellular differentiation wikipedia , lookup
Endomembrane system wikipedia , lookup
Transcript
Lignin • Adds compressive strength • Adds rigidity • Found in cells having supporting (wood) or mechanical function 1 Lignin fills wall (yellow) e.g. in wood – resists compression 2 Plasmodesmata • Connect adjacent cells • Narrow channels that can be opened or closed • Can transport: – – – – Ions RNA Proteins Viruses 3 Plasmodesmata Structure • Desmotubule – Specialized endoplasmic reticulum – Not thought to be open • Cytoplasmic sleeve – Complex structure – Believed to be site of transport 4 5 6 7 8 Plasmodesmata cont. • Types of transport – Symplastic • Through the plasmodesmata – Apoplastic • Through the cell wall • Size exclusion limits • Symplastic domains – Although all cells connected by plasmodesmata, some closed 9 Cell Extensions • Two types of cellular extensions are cilia and flagella. • Cilia are small hairlike projections which beat to move substances. The respiratory tract is lined with cilia which only beat in one direction to move substances up from the lungs. (then we swallow them) • Flagella (flagellum is the singular) are cellular projections which help the cell to move. A flagellum is found on sperm cells and helps them to swim to fertilize the egg. 10 Plant specific organelles • • • • Vacuole Plastid Cell wall Plasmodesmata 11 Plastid development • Must arise from a pre-existing plastid • Start out as a proplastid – Small, undifferentiated plastids – Found in meristems (dividing cells) – Later differentiate • Etioplasts – Chloroplast precursors found in dark grown plants – Have prolamellar bodies 12 Mature types develop from undifferentiated young plastids Types can interconvert e.g tomato ripening 13 Evolution of plastids: Endosymbiosis • Plastids (like mitochondria) have own circular genome, double membrane, ribosomes • Originated as photosynthetic bacteria (cyanobacteria) • Engulfed by larger heterotropic cell • Symbiosis 14