Exam 40: Plant Reproduction

Suppose that 100 pollen grains land on a stigma,and 50 mature seeds are formed in the fruit.What does this indicate about the pollination process and success?

What is an essential part of alternation of generations in plants?

If a hypocotyl does not elongate during seed germination and early seedling growth,where will the cotyledons be?

Charles Darwin experimented with reactions of grass seedlings (monocots)relative to applied auxin (a plant hormone)and light.He used the youngest seedlings with a structure that dicots do not have.What is the name of that structure?

Which of these events occurs first in seed germination?

The egg of a plant has a haploid chromosome number of 12 (n = 12).What is true about the number of chromosomes in the cells of other tissues of this plant?

Which of these is not a step in the formation of an embryo from a zygote in the seed?

Use the following information when answering the corresponding question(s). Whitebark pine (Pinus albicaulis)is an important tree at timberline in the Rocky Mountains and Sierra Nevadas.Its large seeds provide food for grizzly bears,squirrels and other rodents,and many birds,including its major seed disperser,the Clark's nutcracker (Nucifraga columbiana).The Clark's nutcracker has a pouch below its tongue for carrying seeds,which it deposits 10 m to 12 km from a tree.Clark's nutcrackers often store many more seeds than they need for survival;in a single year,one bird can store more than 30,000 seeds.They store 3-5 seeds from one cone in each cache and typically use the seeds for food during spring and summer.When these birds do not harvest the seeds,the seeds germinate and form new whitebark pine trees.(D.F.Tomback.1982.Dispersal of whitebark pine seeds by Clark's nutcracker: A mutualism hypothesis.Journal of Animal Ecology 51:451-67. ) -Refer to the paragraph on whitebark pine seed dispersal by Clark's nutcracker.To conclude that the Clark's nutcracker is a mutualistic seed disperser,not just a predator,you would need to determine that _____.

A gardener in Canada wants to surprise his mother on her birthday and make her favorite Shrubalthea bush flower in May instead of the end of June.The bush is growing in the greenhouse.Which of the following might make the Shrubalthea bush flower early?

The flowering hormone is made in _____ and alters development of _____.

Gardeners purchase packets of seeds that are put in the ground and germinate.Native plant seeds usually need a scarification treatment or a real or simulated winter (stratification),some seeds need light,and others need a smoke treatment.What do these adaptations to the environmental conditions reveal about where the plants grow?

A researcher found a beautiful plant while traveling in Alaska and collected its seeds.When she came back to Florida,she soaked some seeds in pure water and some in water with the hormone gibberellin.When she put seeds to grow in soil,only seeds soaked with gibberellin germinated.The seeds that were soaked in pure water did not germinate because of _____.

If an ovary contains 50 ovules,what is the minimum number of pollen grains that must land in order to form 50 mature seeds?

You find a fruit that has little hooks around the outside of the pericarp.You can assume that _____ is/are the pollinator.

Cottonwood,aspen,and willow trees have beige flowers,with no petals,that appear before the tree's leaves are out in the spring;and they are dioecious.What does that indicate about these trees?

Unripe fruits protect seeds from predation and early germination.What is the major function of ripe fruits?

A summer occupation in the Corn Belt states is de-tasseling the corn: Removing unwanted male flowers so that female flowers on the same plant are pollinated by the desired pollen for the hybrid corn.What does this tell you about corn?

Pollen from a plant with the S₁S₂ genotype is recognized and allowed to germinate on the stigma of the same plant with the S₁S₂ genotype.According to the S-system hypothesis,this indicates that the plant is _____.

The hammer orchids resemble female thyranide wasps and release a chemical signal called pheromone to deceive male thyranide wasps and accomplish pollination.Compared to food-deceiving orchids,is it more or less likely that pollen of hammer orchid will be transferred to the flower of the same species than to flower of the different species?

Mosses and ferns tend to be most abundant in warm,moist climates.Why do mosses and ferns have problems with reproduction in deserts?