Describe the structure and state the functions of flowers.

State the functions of flowers: to aid pollination, give rise to seeds and fruits.

FLOWER contains reproductive parts of the plant. The Function of Flowers: To aid pollination, give rise to seeds and fruits. (Sepals/petals protect the essential parts of the flower, petals aid pollination by attraction).

Draw a vertical section of a monocotyledon flower (not grass) and a dicotyledon flower to show where appropriate: receptacle, tepal, sepal, petal, calyx, corolla, nectary, anther, filament, stamen, stigma, style, ovary and ovule.

FLOWER PARTS

RECEPTACLE (FLOWER PART)

TEPAL

SEPAL

PETAL

CALYX

COROLLA

NECTARY

ANTHER

FILAMENT

STAMEN

STIGMA

STYLE (FLOWER PART)

OVARY

OVULE

State the meaning of ‘monoecious’ and ‘dioecious’ in relation to plants. Know TWO examples of each.

MONOECIOUS Both staminate (male) and pistillate (female) flowers occur on the same plant as separate flowers, e.g., corn – Zea mays/cucumber – Curcuma’s natives.

DIOECIOUS Staminate (male) and pistillate (female) flowers occur on separate plants, e.g., Ilex x altaclerensis “Golden King” or Ginkgo biloba:

MISSING EXAMPLES GIVE_EXAMPLES [2] : monoecious

MALE FLOWER

MISSING EXAMPLES GIVE_EXAMPLES [2] : dioecious

STAMINATE male-flower (adj.)

FEMALE FLOWER

PISTILLATE female-flower (adj.)

HERMAPHRODITE Hermaphrodite: All the flowers have both male and female in the same flower on the same plant, e.g., many plants: Fuchsia “Voodoo” Solanum lycopersicum Tomato

State the meaning of the term ‘pollination’.

POLLINATION The transfer of pollen from an anther to a stigma. wind- insect- and Other forms: Animals, bats, humming birds, water.

CROSS POLLINATION Cross pollination (which is preferred in nature as it promotes diversity) is where pollen is transferred between different plants of the same species – needed by most Apple cultivars;

SELF POLLINATION Self-pollination is where the pollen from the same flower/plant will fertilise itself, e.g., Apple “Self Fertile Queen Cox” or Cherry “Stella”;

SELF-INCOMPATIBLE Self-incompatible is where the plant will not fertilise with its own pollen, hence the need for cross pollination in most Apple cultivars, e.g., “Cox’s Orange Pippin” is self-incompatible.

POLLEN

Describe the characteristics of wind and bee pollinated plants - variations in flower structure and pollen.

WIND POLLINATION Usually monoecious, with catkin-like male flowers high up in the plant waving in the wind to scatter vast quantities of small, fine, dry pollen; Female flowers are below the male flowers, very basic structure with no petals but feathery stigma to collect the airborne pollen.

CATKIN

INSECT POLLINATION Flowers, often open and flat, pretty/with lines/spotted, producing scent (especially in winter Sarcococca or bad smelling Arum) producing nectar to attract insects to the flower. Pollen is larger/sticky/rough which tends to stick to the insect. The stigma is often sticky, large and flat. The time of flowers opening may coincide with its pollinator – night for moths. Bees collect nectar and pollen from the flowers for food and in collecting these transfer pollen from anther to stigma and flower to flower.

NECTAR