Science Form 3 Chapter 4 : Reproduction 4.9 Pollination Group members : Nadia Binti Zulkifli(leader) Fatin Syahindah Binti Daud Siti Mardiana Binti Mohd Saini Siva Letchumi a/p Tamil Selvan Nur Hazirah Binti Nordin Nur Shafika Binti Aripin
Pollinatio n
4.9 Pollination
Pollination is the process of transferring ripe pollen from the anther to stigma. There are two type of pollination : 1) Self-pollination – take place when the pollen from the anther of a flower is transferred to the stigma of the same flower or another flower on the same plant. Polen transferred to stigma of same flower anther stigma
Pollen transferred to another flower of same plant anther stigma
2) Cross-pollination- the transfer of pollen of a flower to the stigma of another flower on different plant of the same species. pollen stigma
anther
Table 4.9.1 Comparison between sel-pollination and cross pollination Self-pollination
Cross-pollination
Involves only one plant
Involves two plants of the same species
Requires one or two flowers from the same plant
Requires two flowers from the different plant of the same species
If it involves one flower, both the anther and stigma must mature at the same time. If it involves two flowers, the anther and stigma can mature at different times
The anther and stigma can mature at different times
Less variety in new plants
More variety in new plants
4.9.1 Pollinating agents
4.
Agents of pollination include organisms or media that transfer the pollen grains from the anther to the stigma of a flower. Agents of pollination include humans and animals, wind and water. The structure of flowers have certain characteristics to promote pollination. Wind Is a pollinating agent for most monocotyledonous plant, like maize, grass and paddy. Wind-pollinated flowers usually : white or light in colour, small, have no smell and no nectar. Have long filaments to expose the pollen to wind. Produce plenty of small, light and smooth pollen. The styles and stigma are long. The stigma is feathery to trap the pollen carried by the wind.
1.
Insects
Attracted by big, colourful and scented flowers. When insect lands on the flower to suck nectar for food, pollen sticks to the hairy legs and body of insect. When insect lands on another flower to collect food, the pollen may drop off and stick on the stigma of that flower. Insect-pollinated flowers :
Produce small amounts of pollen. Such pollen is big, sticky, heavy and rough. Their style are short and the stigma has sticky surface.
1.
Animals
Pollinate flower when they suck nectar from the flowers. Such flowers are usually big, colourful, scented, and produce rough and sticky pollen. The pollen sticks to the beak or body of the animals. When animals such a bird sucks out nectar with its long and pointed beak, pollen sticks to the beak.
1.
Water o o o
Is a pollinating agent for water plants like Elodea and Hydrilla. The flower floats on water surface. The water carries the pollen from the pollen from the anther to the stigma. Elodea
Hydrilla
Table 4.9.2 Comparison between wind and insect pollinated flowers Wind-pollinated flower
Insect-pollination flower
Small, pale coloured, not scented, no nectar
Big, brightly coloured, scented, nectar present
Long filament with big anther at the end, filament sways in the wind and pollen disperses
Short filament and small anther at the end
Plenty of small, light and smooth pollen
Big, rough, sticky and less amount of pollen
Long style
Short style
Long and feathery stigma
Short and sticky stigma
The Advantage Of Cross-pollination
New varities of plants Healthier plants which can adapt better to changes in invironment Healthier seeds New plants that are more resistant to pest and diseases
Use Of Cross-pollination In Agriculture
Human act as pollinating agent; widely used in the field of agriculture to produce better and higher quality crops. In Malysia, the various agricultural agencies like the Malayan Agriculture Research and Development Institute (MARDI) and the alaysian Palm Oil Bord (MPOB) are responsible for carrying out research to increase the quantity and qualiti of agricultural products. Among the new crop plants produce by cross-pollination are oil palm, maize plants and papaya plants.
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