Flashcards in Plant structure Deck (17):
What are the two forms of plant growth?
Primary (apical meristems) and secondary (lateral meristems)
What are the characteristics of primary plant growth?
rapidly dividing cells, lengthens root and stems. Herbs are only apical meristems
What are the characteristics of secondary plant growth?
Lateral meristems (cambia), has vascular cambium (add layers of vascular tissue-xylem and phloem resulting in annual growth rings), Cork cambium (replaces epidermic with thicker, tougher periderm), Increase thickness, mainly in woody plants
What are the characteristics of the roots?
Is anchor in soil (taproot allows for tall plants), absorbs minerals and water (in root hairs), Stores carbs and other reserves
What are the different types of roots?
Fibrous root (many), Taproot (main, vertical), Taproot system (vertical with offshoots), primary (first root from embryo) and lateral (branching roots off primary)
What are the characteristics of stems?
function-elongation and orientation of shoot maximising photosynthesis, Terminal/axillary buds are buds on stem containing apical meristem. Modified stems, Rhizoids, stolons (“runners”) and tubers (potatoes)
What are the characteristics of leaves?
Main photosynthesis organ, Intercept light, Gas exchange with atmosphere, Dissipation of heat, Defence against herbivores and pathogens.Modified leaves, Tendrils, spines (cacti), storage (onion) and reproductive
What are internal plant responses to signals?
Hormones:control of growth and development, mediation of response to environmental stimuli
What are the external plant responses to signals?
Sunlight (season change), Herbivores, Pathogens, Gravity, Environmental stresses (drought, flooding)
What is photosynthesis?
Plants generate o2 and carbs from co2, water and energy in chloroplast, open stomata allows for diffusion of co2
How do plants transport nutrients?
Phloem – sugars from (usually) leaves to where needed (usually roots and growth sites), 2 way path and uses energy
Xylem – water and dissolved minerals upwards from roots to shoots, on inside of phloem, 1 way and no energy used
How do plants gain nutrition?
Nutrition is drawn from above ground (co2 and sunlight from leaves), below ground (water and minerals from roots) and in between (long distance transport of water and nutrients support-stems)
What is asexual reproduction in plants?
Only 1 plant, simple, fast and little energy used, stronger than seedlings however no genetic variation and passing genetic diseases.
What is double fertilisation?
1 sperm to egg to make zygote, 1 sperm to make endosperm (food part of a seed)
What is the purpose of fruits?
Protection of seed and aiding dispersal by wind or animals
What is the purpose of flowers?
They are the reproductive shoots