Buscar
Estás en modo de exploración. debe iniciar sesión para usar MEMORY

   Inicia sesión para empezar

level: 7.9 Investigating transport in plants

Questions and Answers List

level questions: 7.9 Investigating transport in plants

QuestionAnswer
Experiments that prove mass flow theory- Ringing experiments - Tracer experiments
Ringing experiments- If a ring of bark (which includes xylem + phloem) is removed from a woody stem - Bulge forms above ring - The fluid from bulge has a HC of sugars than the fluid from below the ring - Evidence that there's a downward flow of sugars
Radioactive tracers- Such as radioactive carbon - Can be used to track movement of organic substances in a plant
Radioactive tracers experiment- Supplying part of plant with a radioactive substance - It will be present in organic substances e.g sugars, moved by translocation - Can be tracked using autoradiography - Results show translocation of substance from source to sink
Autoradiography- Tracks movement of substances - Shows where radioactive tracer has spread - Plant is killed - Plant placed on photographic film - Radioactive substance present where film is black
More evidence that translocation of organic molecules occurs in the phloem- Phloem cut sap oozes out, pressure gradient exists - Aphids
Aphids- Type of insect that feeds on plants - Pierce phloem, then bodies are removed leaving mouthparts, allows sap to flow out - Sap flows out quicker towards the leaves than down stem, pressure gradient exists