E. coli has at least four individual topoisomerases (I through IV). Those of type I (topoisomerases I and III) generally, relax DNA by removing negative supercoils (increasing Lk).

TLS Online TPP Program

#Id: 10255

#Unit 6. System Physiology – Plant

The synthesis of Group 3 D‐7 family* LEA proteins, storage proteins, and lipids is promoted by ABA

TLS Online TPP Program

#Id: 10256

#Unit 6. System Physiology – Plant

Precocious germination in the ABA-deficient vp14 mutant of maize. The VP14 protein catalyzes the cleavage of 9-cis-epoxycarotenoids to form xanthoxal, a precursor of ABA. 

TLS Online TPP Program

#Id: 10257

#Unit 6. System Physiology – Plant

when seed abscisic acid (ABA) content is highest 

Accumulation of disaccharides and oligosaccharides

Synthesis of storage proteins

Synthesis of late-embryogenesis-abundant (LEA) proteins

Synthesis of small heat shock proteins (smHSPs)

Activation of antioxidative defenses

Changes in the physical structure of cells

Gradual increase in cell density

TLS Online TPP Program

#Id: 10258

#Unit 6. System Physiology – Plant

ABA is transported by both the xylem and the phloem, but it is normally much more abundant in the phloem sap

TLS Online TPP Program

#Id: 10259

#Unit 6. System Physiology – Plant

ABA synthesized in the roots can also be transported to the shoot via the xylem. The concentration of ABA in the xylem sap of well-watered sunflower plants is between 1.0 and 15.0 nM, the ABA concentration in water stressed sunflower plants increases to as much as 3000 Nm (3.0 μM)

TLS Online TPP Program

#Id: 10260

#Unit 6. System Physiology – Plant

As the soil dried out, the water potential of the leaf decreased, and the ABA content and stomatal resistance increased. The process was reversed by rewatering.