JOURNAL ARTICLE

The differential response of photosynthesis to high temperature for a boreal and temperate Populus species relates to differences in Rubisco activation and Rubisco activase properties

Moh'd I Hozain, Michael E Salvucci, Mohamed Fokar, A Scott Holaday
Tree Physiology 2010, 30 (1): 32-44
19864261
Significant inhibition of photosynthesis occurs at temperatures only a few degrees (<or= 10 degrees C) above the optimum, resulting in a considerable loss of potential productivity. Most studies of heat stress have focused on crop or weedy annual plants, whereas similar studies with trees have been limited in number. As temperature is a major factor limiting the geographic ranges of most plants, the aim of this study was to use two Populus species adapted to contrasting thermal environments for determining the factors that constrain photosynthetic assimilation (A) under moderate heat stress in tree species. Consistent with its native range in temperate regions, Populus deltoides Bartr. ex Marsh. exhibited a significantly higher temperature optimum for A than did Populus balsamifera L., a boreal species. The higher A exhibited by P. deltoides at 33-40 degrees C compared to that for P. balsamifera was associated with a higher activation state of Rubisco and correlated with a higher ATPase activity of Rubisco activase. The temperature response of minimal chlorophyll a fluorescence for darkened leaves was similar for both species and was not consistent with a thylakoid lipid phase change contributing to the decline in A in the range of 30-40 degrees C. Taken together, these data support the idea that the differences in the temperature response of A for the two Populus species could be attributed to the differences in the response of Rubisco activation and ultimately to the thermal properties of Rubisco activase. That the primary sequence of Rubisco activase differed between the species, especially in regions associated with ATPase activity and Rubisco recognition, indicates that the genotypic differences in Rubisco activase might underlie the differences in the heat sensitivity of Rubisco activase and photosynthesis at moderately high temperatures.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
19864261
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"