Plant Structure and Function Flashcards
Explain the parts and function of the root system in plants.
Functions - Anchoring the plant in the soil - Absorbing and storing water and nutrients - Transporting water and nutrients Parts - Taproot: main vertical root - Lateral roots: grow out from taproot
Explain the Parts and function of the stem in a plant.
Stems contain nodes (places where leaves attach) and internodes (between nodes)
At the end of the stem is the terminal bud (main point of growth)
- if the terminal bud is removed, plant stimulates auxiliary bud (places where leaves meet stems)
Explain the Parts and Function of leaves
Leaves are the main site of photosynthesis
Parts
- Petiole: stem of leaf
- Apex: tip, furthest from the petiole
- Margin: outer edge
- Base: where blade connects to the petiole
- Stipules: small leafy growths attached to the petiole
Explain the xylem in a plant and its function.
Carry water and minerals up the plant by 2 processes
Transpiration: evaporation which causes passive transport (high concentration to low concentration)
Root pressure: when the mineral content in roots is high, they absorb water to be pulled through the plant by the xylem
Explain the Phloem and its function in a plant
Transports food made by leaves throughout the plant
Sieve-tube cells: narrow cells that resemble tubes connected to each other in chains to transport sugars and organic molecules
Companion Cells: the survival, feeding and maintenance of sieve-tube cells depends on a companion cell
How are plant structures supported
Supported mainly by the xylem, when plant is hydrated, the water pushes against the cell walls providing structure
What is the difference between a stem tuber and a root tuber?
Stem Tuber: Grows above ground and stores nutrients in a bulge in the stem
Root Tuber: Grows underground and develops both shoots and roots, stores nutrients
Explain the different methods of plant propagation.
Stem cutting: stem is cut forming a callus to retain water and nutrients, adventitious roots develop from the callus
Leaf Cutting: can be at the blade, petiole, leaf bud or leaf section, different cuts determine whether a plant will grow or a root system
Root cutting: can produce new shoots (grows up)
Grafting: combining a stock (root system) and a scion (twig or branch) to get the DNA of the scion and the root system of the stock
What are the factors that affect plant growth?
Sunlight: needed for photosynthesis
- Phototropism: plants move towards sunlight when light is indirect
Soil pH: 6.4 is ideal (can differ depending on plant)
Water: required for structure and photosynthesis, too much causes roots to rot
Gravity: roots bend and grow downward in most cases for better access to water, plant can stand back up if knocked over
What are the essential plant nutrients?
Macronutrients: highly essential
- Carbon, oxygen, hydrogen, nitrogen, phosphorus and sulphur
Micronutrients: elements required in very small amounts
- Chlorine, iron, manganese, boron, zinc, copper, nickel and molybendum
Nitrogen: Primary macronutrient, component of chlorophyll
Fertilizers: 3 main ingredients, nitrogen, phosphorus, and potassium, labelled as N-P-K
Explain herbicides
Used to kill unwanted plants making more nutrients available for desired plants
Come in selective (only kill certain plants) and non-selective (kill everything)
Explain the process of photosynthesis
Chloroplasts (mainly found in mesophyll) contain chlorophyll which absorbs energy from the sun
Carbon dioxide enters the leaf through the stomata and the oxygen exits the same way
6CO2 + 12H2O + light energy = glucose + 6O2 +6H2O
Explain the 2 Stages of photosynthesis
Light Reaction: conversion of light energy into chemical energy
- light energy absorbed by chlorophyll
- light energy causes H2O to separate
- hydrogen accepted by NADP creating NADPH
- ATP created by energy from water molecules
Calvin cycle: uses the energy from the NADPH and ATP in light cycle to convert carbon dioxide and other elements into glucose
Explain the ways asexual reproduction occurs in plants
Stem:
- Stolons: some plants have long horizontal stems that form above ground that can take root becoming a plant
- Rhizomes: same as stolon but horizontal stem is underground
- Bulbs: contains a very short stem with leaves packed closely together
Roots: some plants grow a new plant via their roots
Leaves: small plants called plantlets grow along the mature stem of parent
What are some advantages and disadvantages of asexual reproduction?
ADV:
- desirable traits are kept
- doesnt take long
- good chance of survival because they are mature
DISADV:
- No genetic variation (plants could get wiped out)
- Offspring need to compete with parents for nutrients
