ORIENTATION RESPONSES IN PLANTS

ORIENTATION RESPONSES IN PLANTS

Plants are autotrophs – making food from photosynthesis.

Apart from reproductive organs (flowers) plant structure and functions are adapted for photosynthesis directly or indirectly.

ORIENTATION RESPONSES IN PLANTS

Plants are autotrophs – making food from photosynthesis.

Apart from reproductive organs (flowers) plant structure and functions are adapted for photosynthesis directly or indirectly.

Unable to move from where they germinate, but can move leaves and stems.

ORIENTATION RESPONSES IN PLANTS

Plants are autotrophs – making food from photosynthesis.

Apart from reproductive organs (flowers) plant structure and functions are adapted for photosynthesis directly or indirectly.

Unable to move from where they germinate, but can move leaves and stems.

Movements are much slower than animals because the cellulose cell wall of plant cells prevents repid change in cell shape.

ORIENTATION RESPONSES IN PLANTS

Plants are autotrophs – making food from photosynthesis.

Apart from reproductive organs (flowers) plant structure and functions are adapted for photosynthesis directly or indirectly.

Unable to move from where they germinate, but can move leaves and stems.

Movements are much slower than animals because the cellulose cell wall of plant cells prevents repid change in cell shape.

Plant movements are limited to changes in cell turgor (nastic responses) or growth (tropisms).

TROPISMS

Growth responses – due to abiotic factors (light intensity, chemicals, gravity, water and touch).

TROPISMS

Growth responses – due to abiotic factors (light intensity, chemicals, gravity, water and touch).

Response to put the plant into favourable conditions and away from unfavourable.

TROPISMS

Growth responses – due to abiotic factors (light intensity, chemicals, gravity, water and touch).

Response to put the plant into favourable conditions and away from unfavourable.

Eg – growth towards maximum light intensity for photosynthesis in a forest.

https://www.youtube.com/watch?v=zctM_TWg5Ik

TROPISMS

Positive phototropism – growth of a stem towards light.

Positive gravitropism (aka geotropism) – growth of young root from the seed downwards. Anchoring the plants and enabling uptake of water and nutrients.

TROPISMS

Positive phototropism – growth of a stem towards light.

Positive gravitropism (aka geotropism) – growth of young root from the seed downwards. Anchoring the plants and enabling uptake of water and nutrients.

Negative gravitropism – growth of the young shoot upwards towards the surface.

TROPISMS

Positive phototropism – growth of a stem towards light.

Positive gravitropism (aka geotropism) – growth of young root from the seed downwards. Anchoring the plants and enabling uptake of water and nutrients.

Negative gravitropism – growth of the young shoot upwards towards the surface.

Positive hydrotropism – growth of roots towards a water source.

TROPISMS

Positive phototropism – growth of a stem towards light.

Positive gravitropism (aka geotropism) – growth of young root from the seed downwards. Anchoring the plants and enabling uptake of water and nutrients.

Negative gravitropism – growth of the young shoot upwards towards the surface.

Positive hydrotropism – growth of roots towards a water source.

Positive chemotropism – pollen tubes growing down a stigma towards the ovary is guided by chemicals. This response ensures male gametes reach female gametes so fertilisation can occur.

TROPISMS

Positive phototropism – growth of a stem towards light.

Positive gravitropism (aka geotropism) – growth of young root from the seed downwards. Anchoring the plants and enabling uptake of water and nutrients.

Negative gravitropism – growth of the young shoot upwards towards the surface.

Positive hydrotropism – growth of roots towards a water source.

Positive chemotropism – pollen tubes growing down a stigma towards the ovary is guided by chemicals. This response ensures male gametes reach female gametes so fertilisation can occur.

Positive thigmotropism – growth of stem of climbing plants around a host plant.

https://www.youtube.com/watch?v=pCFstSMvAMI