The rupture and fractionation do not usually occur in the water column in vessel/tracheids during the ascent of sap because of 

  • lignified thick walls

  • cohesion and adhesion

  • weak gravitational pull

  • tranpiration pull

Roots play insignificant role in absorption of water in

  • Sunflower

  • Pistia

  • Pea

  • Wheat

Which one gives the most valid and recent explanation for stomatal movements?

  • Transpiration

  • Potassium influx and efflux

  • Starch hydrolysis

  • Guard cell photosynthesis

Which of the following is made up of dead cells?

  • Xylem parenchyma

  • Collenchyma

  • Phellem

  • Phloem

Which of the following criteria dows not pertain to facilitate transport?

  • Requirement of special membrane proteins

  • High selectivity

  • Transport saturation

  • Uphill transport

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