Assignment 4

Question 1

when did global production of aquatic plants take a significant leap?

Answer 1

in the early 1990’s, followed with a steep incline

Question 2

since the early 1990’s there has been a steady increase in aquatic plants. Which species have contributed to this increase, and which species have declined?

Answer 2

Increase:
-Porphyra
-Laminaria
-Wakame
-Gracilaria (weakly)
-Eucheuma (carrageenan)
-Undaria (since 1995)
Decline:
-Gelidium
-Undaria (crashed in 1995)

Question 3

how far back has the use of seaweed as food been traced?

Answer 3

fourth century in japan, sixth century in China

Question 4

which three countries are the largest consumers of aquatic plants?

Answer 4

China, Japan, and Korea

Question 5

What percentage of total aquatic plants are produced through aquaculture?

Answer 5

more than 90%.

Question 6

how much seaweed does china harvest annually?

Answer 6

approx. 5 million wet tonnes

Question 7

What are the three most common aquatic plants harvested?

Answer 7

Kombu (Laminaria), wakame (Undaria), and nori (porphyra).

Question 8

what are the three hydrocolloids?

Answer 8

agar, alginate, and carrageenan.

Question 9

what is a hydrocolloid, and what is it used for?

Answer 9

brown and red seaweeds which produce non-crystalline substances with large molecules which dissolve in water to produce a viscous solution.
They are used as thickening agents.

Question 10

what are some uses for seaweed other than as a human food source?

Answer 10

• seaweed meal as an additive to animal feed (brown seaweeds)
• fertilizer as liquid seaweed extract (brown seaweeds)
• cosmetic products such as creams and lotions (hydrocolloids)
• biofuel (seaweed, algae)
• wastewater treatment (in development)

Question 11

name the stages of laminaria’s sexual reproduction

Answer 11

HAPLOID
1) zoospore
2) embryospore
3)germination of embryospore
4)new gametophyte
5)gametophyte
6)mature oogonium / spermatozoid discharged from antheridium
7) discharged egg from oogonium/ biflagellate spermatozoid
8) fertilization
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DIPLOID
9) zygote
10) 7-celled seedling
11) young sporophyte
12) robust sporophyte
13) mature sporophyte with sporangial sori