Chapter 29, Problem 1DAA

Who’s the Pollinator? Massonia depressa is a low-growing succulent plant native to the desert of South Africa. The dull-colored flowers of this monocot develop at ground level, have tiny petals, emit a yeasty aroma, and produce a thick, jellylike nectar. These trails led researchers to suspect that desert rodents such as gerbils pollinate this plant. The researchers trapped rodents in areas where M. depressa grows and checked them for pollen (FIGURE 29.7A,B). They also put some plants in wire cages that excluded mammals, but not insects, to see whether fruits and seeds would form in the absence of rodents (FIGURE 29.7C).

A The dull petalless, ground-level flower of Massonia depressa are accessible to rodents, who push their heads through the stamens to reach the nectar at the bottom of floral cups. Note the pollen on the gerbil’s snout.

B Evidence of visits to M. depressa by rodents.

	Mammals allowed access to plants	Mammals excluded from plants
Percent of plants that set fruit	30.4	4.3
Average number of fruits per pant	1.39	0.47
Average number of seeds per plant	20.0	1.96

C Fruit and seed production of M. depressa with and without visits by mammals. Mammals were excluded from plants by wire cages with openings large enough for insects to pass through. Twenty-three plants were tested in each group.

FIGURE 29.7 Testing pollination of M. depressa by rodents.

How many rodents were captured? Of these, how many showed some evidence of ingesting M. depressa pollen?

Summary Introduction

To determine: The number of rodents captured.

Introduction: In the flowering plants, pollination is one of the necessary processes for sexual reproduction. Pollination involves the arrival of the pollen grains on a receptive stigma. Pollination takes place with the help of pollinating agents such as by wind or animal. Pollinators are the animal pollination vectors. The pollen, nectar, and other rewards are used by the plants to attract the pollinators. A plant called Massonia depressa is a low-growing moist plant that is commonly found in the semi-desert of South Africa. The leaves of these plants are sometimes maroon or green colored. The desert rodents such as gerbils are found to pollinate Massonia depressa plant.

Explanation of Solution

The environmental agents or animals are the pollination vectors, which help to transfer pollen from anther to stigma. As given in the data, Massonia depressa consists of dull-colored flowers with little petals, which usually grow at ground levels that are gathered together between the leaves. These petals have a tendency to release a yeasty aroma in order to make nectars. All adaptations in these flowers attract pollinators and rodents that help the flowers in pollination.

Refer Fig.29.7B, “Evidence of visits to M.depressa by rodents” in the textbook. The researchers believed that the gerbils, the desert rodents, pollinated this plant. In order to confirm this, they captured 13 rodents and checked for pollen on their snout and in the feces.

Conclusion

The number of rodents captured is 13.

Summary Introduction

To determine: The number of rodents that shows some evidence of ingesting Massonia depressa.

Introduction: A plant called Massonia depressa is a low-growing moist plant that is commonly found in the semi-desert of South Africa. The leaves of these plants are sometimes maroon or green colored. The desert rodents such as gerbils are found to pollinate Massonia depressa plant.

Explanation of Solution

The researchers observed that out of 13 rodents caught, seven of them had pollen on their snout. This sign suggested that the rodents pushed their heads through the stamens to arrive at the nectar. Also, out of the 13 rodents caught, nine of them had pollen in the feces. Some of the members of rodents also had both pollen on their snout and in their feces.