Phenotypic variation that is due to genetic differences is referred to as heritability. It can be the Broad-sense heritability and Narrow-sense heritability, the Broad-sense heritability which is ranges from 0 to 1. Identify the correct prediction about these ranges?

a) 0 is all of the phenotypic variance results from differences in genotype

b) 0 is all of the phenotypic variance results from environmental variation

c) 1 is all of the phenotypic variance results from differences in genotype

d) 1 is all of the phenotypic variance results from environmental variation

#Question id: 11739

#Unit 6. System Physiology – Plant

which of the following compound is resist to cleave by cytokinin oxidase and why?

#Question id: 11807

#Unit 6. System Physiology – Plant

Given below are few statements regarding the cytokinin signalling pathway;

a) Cytokinin inhibits the activation of a Cdc25- like phosphatase, whose role is to remove an inhibitory phosphate group from the Cdc2 kinase

b) Cytokinin oxidase irreversibly inactivates cytokinins, and it could be important in regulating or limiting cytokinin effects

c) Cytokinin signal transduction pathway is completed on multiple places such as ER, Cytosol and Nucleus

d) Elevation of endogenous cytokinin levels in transgenic Arabidopsis results in overexpression of the KNOTTED homeobox transcription factor homologs KNAT1 and STM—genes 

Which of the following combinations  from the given above statements is correct?

#Question id: 11808

#Unit 6. System Physiology – Plant

In addition to the free bases, which are the only active forms, active cytokinin levels are decreased through;

a) Addition of sugar molecule to the 3, 7, or 9 nitrogen of the purine ring, called glycosylation-mediated inactivation

b) cis-trans isomerisation of zeatin

c) Irreversible cleavage by cytokinin oxidases.

Which of the following is incorrect?

#Question id: 11809

#Unit 6. System Physiology – Plant

Shortly after the discovery of kinetin, it was observed that the differentiation of cultured callus tissue derived from tobacco pith segments into either roots or shoots depends on the ratio of auxin to cytokinin in the culture medium. Whereas

a) high auxin:cytokinin ratios stimulated the formation of roots

b) high auxin:cytokinin ratios stimulated the formation of shoots

c) low auxin:cytokinin ratios led to the formation of shoots

d) low auxin:cytokinin ratios stimulated the formation of roots

which of the following combination is correct about the ratio of auxin to cytokinin

#Question id: 11810

#Unit 6. System Physiology – Plant

An experiment was done to see the effect of auxin: cytokinin ratios on morphogenesis can also be seen in crown gall tumors by mutation of the T-DNA of the Agrobacterium Ti plasmid,

I) Mutating the ipt gene (the tmr locus) of the Ti plasmid blocks zeatin biosynthesis in the infected cells

II) mutating either of the genes for auxin biosynthesis (tms locus)

Given some results about these above mutations ,

a) equal auxin to cytokinin ratio form undifferentiated callus tissue

b) high auxin:cytokinin ratio in the tumor cells causes the proliferation of roots instead of undifferentiated callus tissue

c) lowers the auxin:cytokinin ratio and stimulates the proliferation of shoots

What would be the result of these two mutation ?

#Question id: 11811

#Unit 6. System Physiology – Plant

The expression of  IPT gene in the stress is driven by___