Jun 9, 2011

Translocation of Organic Solutes

Not only do plants transport water and minerals from the roots to the leaves, they also transport organic nutrients to the parts of plants that need them. This includes young leaves, flowers, seeds, fruits and especially the roots. Phloem tissues transport organic nutrients. This is shown by feeding habits of aphids.

Feeding Habit of Aphids: The feeding habit of small insects that suck the juice of plants, gives us valuable information about translocation. An aphid feeds on leaves and stem. It inserts the mouth parts or stylets or proboscis into a sieve tube, which contains sugary fluid.

Honey Dew: The sieve tubes are under high turger pressure. The sieve tube sap is forced through the gut of the aphid. The sap comes out of the posterior and of the gut as droplets called honey dew. 

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