Chapter 37, Problem 1Q

Summary Introduction

To review:

The effect of gigas (gi) mutant allele on the pea plant’s flowering, with reference to the data provided in Table 1 below.

Table 1: The effect of gigas mutant allele on the pea plant’s flowering.

Strains	Photoperiod (hours of light provided to the plants)
		12 h	16 h	24 h
Gigas (gi mutant)	54 nodes	43 nodes	Only vegetative growth
Wild type (WT)	20 nodes	16 nodes	15

Introduction:

The flowering of a plant depends on the types of genes that are essential for its flowering. In pea plants, the effects of genes are often studied with the help of grafting. When wild type (WT) is grafted with the mutant type of plant stem, the mobile signals get transferred from one stem to another, thus compensating the absence of a functional allele in the mutant type.

Explanation of Solution

In Table 1, the number of nodes in case of the gi allele is more as compared to the WT, after 12 hours and 16 hours of light exposure. This means that the vegetative growth of plant is more in mutant allele as compared to the WT. When the vegetative growth of a plant is more, the flowering occurs very late because flowering takes place only after the vegetative growth of a plant gets stopped.

After 24 hours of light exposure, only 15 numbers of nodes are noticed in the WT type whereas, in the plants, with gi allele, only the vegetative growth is observed. In the mutant plants, flowering is never observed even after 24 hours of light exposure.

Conclusion

Thus, it can be concluded that from the given table that the mutant allele gi, delays the flowering in the plants, whereas the plants with WT allele undergo the normal period of flowering.