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Crop physiology and plant nutrition (Subject) / Crop Physiology and Plant nutrition (Lesson)
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- What are the origins of Cl in soils? (3) -marine sediments -precipitation -Cl-apatite
- Which conditions can lead to leaching/accumulation of Cl? -accumulation under arid conditions and due to salt intrusion -leaching under humid conditions
- Which process is mainly responsible for transport of Ca, Mg and Cl to root surfaces? Mass flow
- Where do symptoms of Ca deficiency show first and why? -on younger leaves (Ca immobilized in cell walls) -on fruits (low transpiration, low supply via the xylem)
- What types of fertilizer can be used for foliar Ca application? (2) -CaCl2 -Ca(NO3)2
- How is Mg taken up by plants and where is it found? (5) -taken up as Mg2+ -found in cytosol (50%) -sorbed (30%) -bound in chloroplasts (15%) -found in ribosomes
- How is Mg transported in plants and where do symptoms of deficiency show first? Mg can be mobilized in the phloem Deficiency symptoms show first on older leaves
- How is Cl taken up by plants, where is it found and how is it transported? taken up as Cl- found in vacuoles (osmotic function) transported via the xylem and through membranes
- Name the functions of Ca in plants (7) -unspecific enzyme activation -inactivation of IAA -messenger for calmodulin -> Ca2+ is pimped out of the cell -formation of Ca-pectines to stabilize cell walls -osmotic regulation -constituent of various compounds -pollination and root hair growth
- Name the functions of Mg in plants (3) -enzyme activation -binding of the ribosomal subunits -constituent of Chlorophyll
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- Name the functions of Cl in plants (5) -electrostatic balance -osmotic regulation -splitting of H2O in photosynthesis -transport of H+ into the vacuole -reduced starch transport into storage organs
- What is the common unit for Ca fertilizer and how much Ca do they actually contain? name tree limes CaO x 0,715 = Ca CaCO3, Ca0, Ca(OH)2
- What is the common fertilizer unit for Mg and how much Mg is actually contained? name three Mg fertilizers, one for foliar application MgO x 0,603 = Mg epsom salt (MgSO4) foliar MgCl2 MgO
- Where does K mainly originate in the soil? from primary silicates and salt ores
- How is K mostly found in soils? in the solution or sorbed to clay minerals
- How Na mostly found in soils? in the soil solution, as compounds (NaCl) or sorbed to clay minerals
- Which process is mainly responsible for the movement of K+ and Na+ to root surfaces? Diffusion
- How and where is K found in plants? present as K+ only found in cell solution and weakly sorbed to proteins
- How does the K+ concentration change from roots to leaves roots low - leaves high
- In which agricultural processes does Na have a beneficial effect -production of natrophilic plants -increases fodder quality -can substitute K in sugar beet and spinach
- How is K+ taken up by plant roots? -passive uniport through specific channels -symport with H+ (secondary active)
- How is Na+ taken up by plant roots? -passive uniport through channels -active pumping of Na+ out of the root
- Name the functions of K+ in plants -specific and unspecific enzyme activation -activation of ribosomes -osmotic functions -opening and closing of the stomata -more efficient transfer of light energy into chemical energy in photosynthesis and CO2 assimilation -co-transport of K and assimilates into the xylem and phloem (long-distance transport) -co-transport of K-sucrose into the vacuole of storage organs
- What are the physiological impairments caused by K deficiency? (3) -accumulation of lower molecular weight carbohydrates and proteins (pests/diseases) -reduced activity of nitrate reductase -> lower protein formation -lower carbohydrate synthesis -> lower sugar/starch content, lower cellulose content -> lodging
- What are beneficial functions of Na+ in plants? (4) -higher leaf area in sugar beets -thicker leaves -faster closing of the stomata compared to K+ -more efficient transport of sucrose into roots of sugar beets
- What is the common fertilizer unit for K+ and how much K is actually present? name three K fertilizers, one for foliar application K2O x 0,83 = K nitrate of potash (KNO3) for foliar application sulphate of potash muriate of potash