Threshold characteristics display only two possible phenotypes—the trait is either present or absent.

TLS Online TPP Program

#Id: 9281

#Unit 6. System Physiology – Plant

Root hair cellular responses to bacterial Nod factor

TLS Online TPP Program

#Id: 9282

#Unit 6. System Physiology – Plant

Plant genes expressed early, or in the absence of bacterial infection, are termed “early nodulins” or ENOD

TLS Online TPP Program

#Id: 9283

#Unit 6. System Physiology – Plant

Three factors are important in maintaining low O2 concentrations in nodules. 

First, entry of O2 into the nodule is controlled by a variable‐permeability barrier in the nodule parenchyma

TLS Online TPP Program

#Id: 9284

#Unit 6. System Physiology – Plant

O2‐binding plant protein Lb plays an active role in regulating and delivering O2 in the infected cells

Bacterial respiration is the major O2 sink

TLS Online TPP Program

#Id: 9285

#Unit 6. System Physiology – Plant

O2‐sensitive hemoprotein kinase FixL controls a regulatory cascade that activates transcription of nitrogen fixation genes

TLS Online TPP Program

#Id: 9286

#Unit 6. System Physiology – Plant

Plant glutamine synthetase (GS) and NADH‐dependent glutamate synthase (NADH‐GOGAT) are responsible for the initial massimilation of ammonia into organic compounds