JOURNAL ARTICLE
RESEARCH SUPPORT, NON-U.S. GOV'T
Add like
Add dislike
Add to saved papers

The temperature response of photosynthesis in tobacco with reduced amounts of Rubisco.

The reasons for the decline in net CO2 assimilation (A) above its thermal optimum are controversial. We tested the hypothesis that increasing the ratio of Rubisco activase to Rubisco catalytic site concentration would increase the activation state of Rubisco at high temperatures. We measured photosynthetic gas exchange, in vivo electron transport (J) and the activation state of Rubisco between 15 and 45 degrees C, at 38 and 76 Pa ambient CO2, in wild-type (WT) and anti-rbcS tobacco. The Rubisco content of the anti-rbcS lines was 30% (S7-1) or 6% (S7-2) of WT, but activase levels were the same in the three genotypes. Anti-rbcS plants had lower A than WT at all temperatures, but had a similar thermal optimum for photosynthesis as WT at both CO2 levels. In WT plants, Rubisco was fully activated at 32 degrees C, but the activation state declined to 64% at 42 degrees C. By contrast, the activation state of Rubisco was above 90% in the S7-1 line, between 15 and 42 degrees C. Both A and J declined about 20% from T(opt) to the highest measurement temperatures in WT and the S7-1 line, but this was fully reversed after a 20 min recovery at 35 degrees C. At 76 Pa CO2, predicted rates of RuBP regeneration-limited photosynthesis corresponded with measured A in WT tobacco at all temperatures, and in S7-1 tobacco above 40 degrees C. Our observations are consistent with the hypothesis that the high temperature decline in A in the WT is because of an RuBP regeneration limitation, rather than the capacity of Rubisco activase to maintain high Rubisco activation state.

Full text links

We have located links that may give you full text access.
Can't access the paper?
Try logging in through your university/institutional subscription. For a smoother one-click institutional access experience, please use our mobile app.

For the best experience, use the Read mobile app

Mobile app image

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app

All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

By using this service, you agree to our terms of use and privacy policy.

Your Privacy Choices Toggle icon

You can now claim free CME credits for this literature searchClaim now

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app