Question

Hi, please help me answer all parts of the question. Thanks.

Chapter 39

•Explain how a plant’s etiolation strategy is different from its de-etiolation strategy.

•How is the effect of the plant hormone abscisic acid different from auxin and cytokinins?

•Why do produce merchants sometimes store fruit in containers with extra ethylene?

•What is the basic function of jasmonate hormones in plants?

•What is leaf abscission, and why do plants do this?

•What are two effects of blue light on plants?

•How does the red photosensor phytochrome affect germination of seeds?

Answer 1

Ans- Difference between a plant's etiolation strategy and de-etiolation strategy-:

Etiolation strategy- It refers to the morphological adaptations that a plant exhibits while growing in the dark. During this stage, plants have long, spindly stems, the leaves lack chlorophyll and are stunted.

De-etiolation- It refers to the greening of the plant. During this stage, stem elongation slows, chlorophyll is produced and leaves expand to normal proportions.

Ans- Auxins and cytokinins are the plant hormones that act as growth stimulators whereas abscissic acid acts as growth inhibitor. Hence, abscissic acid inhibits the growth of a plant.

Ans- Produce merchants sometimes store fruit in containers with extra ethylene because ethylene helps to speed up the process of ripening of fruits. Fruits which are raw are stored in extra ethylene.

Ans- Jasmonate hormone is a phytohormone that acts as an important signaling molecule affecting plant response under biotic and abiotic stresses. These hormones regulate a wide range of processes in plants that are growth,photosynthesis and reproductive development.

Ans- Leaf abscission is the process of dropping of leaves by plants. Trees drop their leaves in order to prepare themselves for winter season. During this time, plants shed their leaves on receipt of internal or environmental signals.

Ans- The two effects of blue light on plants are-:

a) Blue light triggers chlorophyll production and thus stimulates photosynthesis.

b) Blue light provides the plants with strong, healthy stems and leaves.

Ans- Phytochromes are a group of red and far red photosensors that play an important role in regulation of seed germination. It triggers the photoinduction of seed germination after irradiation with extremely low fluence light in a wide range of wavelengths. Phytochrome A plays a major role in early events of seed germination and seed de-etiolation as well.