Plant Processes

16.00: Analyze the process of growth in horticultural plants

Processes of plant growth

• Photosynthesis• Respiration• Absorption• Transpiration• Translocation• Reproduction

Photosynthesis

• The food and manufacturing process in green plants that combines carbon dioxide and water in the presence of light to make sugar and oxygen.– Formula:6CO2+6H2O+672Kcal

C6H12O6+6O2

Carbon Dioxide

Water Light Energy

Glucose Sugar

Oxygen

Respiration

• The process through which plant leaves, stems and roots consume oxygen and give off carbon dioxide.

• Plants produce much more oxygen through photosynthesis than they use through respiration.

Absorption

• The process by which plant roots take in water and air

Transpiration

• The process by which plants lose water from leaves and stems through evaporation

Translocation

• The process by which food and nutrients are moved within a plant from one plant part to another

Reproduction

• The plant process that increases plant numbers– usually by seeds

Stages of Plant Growth

• Juvenile-when a plant first starts to grow from a seed

• Reproductive-when a plant produces flowers, seeds and fruits

• Dormant-when a plant rests or grows very little, if any

Plant Cells

• Basic unit of growth• A nucleus and a mass of

protoplasm contained within a plasma membrane

Parts of a Plant Cell

• Nucleus– location of plant’s genetic and

hereditary make-up

• Protoplasm– the living matter of the cell

• Plasma Membrane– surrounds protoplasm and allows for

exchange of nutrients and gases into and out of cell

Parts of a Plant Cell

• Cell Wall– rigid and provides support for the cell

and thus the whole plant

Parts of a Plant Cell

• Other Structures– Chloroplasts– Vacuole– Plastids– Mitochondrion

Parts of a Plant Cell

Plant Cells

Plant tissue

• A group of cells with similar origin and function

• Classified according to their origin, structure and physiology

• Structure of permanent tissue– simple-usually one type of cell– complex-several types of cells

Tissue origin and function

• Meristematic-near tip of stems and roots where cell division and enlargement occur

• Vascular cambium-increase growth in diameter of stems

Simple Tissues

• Epidermal-one-cell thick, outer layer, protects and prevents water loss

• Sclerenchyma-have thickened cell walls and contain fibers to give strength and support to plant structures

Other tissues

• Collenchyma-have thick cell walls that strengthen and support plant structures

• Parenchyma-fleshy part of plant that stores water and nutrients

Phases of the asexual cycle• Vegetative-growth and development

of buds, roots, leaves and stems– cell elongation-stage when cells enlarge– differentiation-stage when cells

specialize

• Reproductive or flowering-plant develops flower buds that will develop into flowers, fruits and seeds

Effects of Light, Moisture, Temperature and Nutrients

on Plants

Light

• Photoperiodism-response of plants to different amounts of light regarding their flowering and reproduction cycles

• Necessary because of photosynthesis• Not enough light causes long, slender,

spindly stems• Too much light will cause plants to dry

out faster

Moisture

• Needed in large amounts because plant tissues are mostly water and water carries nutrients

• Not enough water causes wilting and stunted growth

• Too much water causes small root systems and drowning which is a result of air spaces in soil being filled with water

Temperature

• Needs vary depending on type of plants

• Either too high or too low will have adverse effects

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Nutrients

• Essential for optimal plant conditions

• Has little effect on seed germination

Combining growth factors

• Ideal quantities and quality will give optimum plant growth

• Each has an effect on the other factors

• Unfavorable environmental conditions for plant growth causes diseases to be more severe in their damages to plants