5.5.4: Commercial uses of plant hormones Flashcards Preview

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Flashcards in 5.5.4: Commercial uses of plant hormones Deck (20)
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1
Q

What can artificial auxins be used for?

A

-Preventing leaf and fruit ‘drop’
(useful if there are too many small fruits that are hard to sell, the plant produces fewer, larger fruits)
-Promote flowering.

2
Q

How are auxins used when taking cuttings?

A
  • Dipping ends of a cutting in rooting powder encourages root growth.
  • Contains auxins and talcum powder.
3
Q

How are auxins used tp promote the growth of seedless fruit?

A
  • Treating unpollinated flowers with auxin promotes growth of seedless fruit.
  • Auxin promotes ovule growth which triggers the automatic production of auxin by tissues in the developing fruit, helping to complete the developmental process.
4
Q

How are auxins used as herbicides?

A
  • to kill weeds.
  • Man-made so plants find them hard to break down and they can act within the plant for longer
  • promote shoot growth so much that the stem cannot support itself, buckles and dies.
5
Q

Why are cytokinins used to prevent the yellowing of lettuce after being picked?

A

They can delay leaf senescence.

6
Q

Why are cytokinins used in tissue culture to help mass-produce plants?

A
  • Cytokinins promote bud and shoot growth from small pieces of tissues taken from a parent plant.
  • This produces a short shoot with a lot of side branches, which can be split into lots of smaller plants.
  • Each of these is then grown separately.
7
Q

How are gibberellins used in citrus fruit production?

A

-They delay senescence in citrus fruit, extending the time fruits can be left unpicked, and making them available for longer in the shops.

8
Q

How are gibberellins acting with cytokinins involved in apple production?

A

-They make apples elongate, improving their shape.

9
Q

How are gibberellins used in grape production?

A
  • Without gibberellins, bunches of grapes are very compact which restricts growth.
  • With gibberellins, the grape stalks elongate, they are less compacted, rapes get bigger.
10
Q

When barley seeds germinate, what does the aleurone layer of the seed produce?

A

-Amylase enzymes that break down the stored starch into maltose.

11
Q

What are the genes for amylase production in barley seeds switched on by?

A
  • Naturally occurring gibberellins.

- Can be sped up by adding gibberellins.

12
Q

Wy are sugar canes sprayed with gibberellins?

A
  • Stimulates growth between nodes making stems elongate.
  • Useful as sugar cane stores sugar in the cells of the internodes.
  • More sugar is available from each plant.
13
Q

How are gibberellins used in plant breeding?

A

-By inducing seed formation from young trees.

14
Q

How can plants be made to stop producing gibberellins?

A

-Spraying plants with gibberellin synthesis inhibitor.

15
Q

WWhy can preventing plants from producing gibberellins be useful?

A
  • Keeps flowers short and stocky.

- Ensures internodes of crop plants stay short, helping to prevent lodging.

16
Q

What is lodging?

A
  • Happens in wet summers.
  • Stems bend over because of the weight of the water collected on the ripened seed head.
  • Crops difficult to harvest.
17
Q

Ethene is a gas and cannot be sprayed directly. What solution have scientists come up with?

A

-Thy developed 2-chloroethylphosphoric acid, which can be sprayed in solution, is easily absorbed and slowly releases ethene inside the plant.

18
Q

What do the commercial uses of ethene include?

A
  • Speeds up fruit ripening (apples, tomatoes, citrus)
  • Promotes fruit drop (cotton, cherries, walnut.
  • Promotes female sex expression in cucumbers, reducing the chance of self-pollination.and increasing yield.
  • Promoting lateral growth in some plants, yielding compact flowering stems.
19
Q

How can ethene synthesis be inhibited?

A
  • Storing fruit at low temp., with little O2 and high CO2 levels prevents ethene synthesis this preventing ripening.
  • Silver salts, increase the shelf life of cut flowers.
20
Q

How can restricting ethene’s effects be useful?

A
  • Fruit stored for longer.

- Essential when shipping unripe bananas from the Caribbean.