Conflict between chlorophyll and air space

用戶36244

2007-02-10 8:17 am

In palisade mesophyll, there are cells packed regularly, comparing with spongy mesophyll which contains lots of air space for gas exchange, palisade mesophyll would be too compact to take place gas exchange. So, although palisade mesophyll contains denser chlorophyll, would the rate of photosynthesis be affected by the absence of air space?

回答 (2)

莫愁

2007-02-13 3:26 am

✔ 最佳答案

photo = photosynthesis
The answer is NO.
First,.you must know that in a plant, there are several parts containing chloroplasts that can undergo photo. And the question is which part of the plant can take up highest portion of photo. For example, those parts written below carry out photo.due to the present of chloroplasts.
(1)palisade mesophyll
(2)spongy mesophyll
(3)guard cells

However, only (1)has a large portion of chloroplast, comparing (2) and (3). Hence, once the gas CO2 diffuse through spongy mesophyll and reach (1), the abundant chloroplast in (1) will carry out carbon fixation and thus sugar willl be produced.

The rate of photo, doesn't affect by whether (1) is absence of air space or not. Since the more the chloroplast, the faster the rate of photo is. 只要有CO2可以由(3)到(2)再去(1), (1)就可以photo.但是它的photo rate會受到guard cell的閉合而減少.因為在這個情況下,真的是absence of air ( CO2). 在guard cell close 時,CO2根本沒有可能入到(2)及再去(1),所以rate of photo才會減少.

希望你明白我在說些什麼

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用戶122481

2007-02-14 7:25 pm

but I think it may affect photosytheic rate in a certain extand, but not the most critical factor
since air space provide a greater surface area for gases exchange, CO2 can enter cell in a greater rate.

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