Are red leaf phenotypes more or less fit? The case of winter leaf reddening in Cistus creticus

作者：Nikiforou Constantinos; Zeliou Konstantina; Kytridis Velissarios Phaedon; Kyzeridou Alexandra; Manetas Yiannis^*

来源：Environmental and Experimental Botany, 2010, 67(3): 509-514.

DOI：10.1016/j.envexpbot.2009.09.005

• Anthocyanins
• Chlorophyll fluorescence
• Growth
• Photosynthetic performance
• Reproductive effort
• Reproductive success

Winter leaf reddening occurs in some plants as a response to the combination of cold temperatures and high light. Hence, a protective function against photoinhibition of photosynthesis has been suggested. However, it is unknown whether the leaf anthocyanic trait confers long term benefits to the plant and to that aim parameters related to fitness were measured.
We took advantage of intra-species variation in the expression of the red leaf character displayed by the Mediterranean shrub Cistus creticus, a held of which during winter becomes a mosaic of green and red individuals under apparently similar environmental conditions. The red individuals are known to be more sensitive to winter photoinhibition of photosynthesis, hence anthocyanins might serve a compensatory function through light screening and/or detoxifying reactive oxygen species. If anthocyanins are indeed beneficial in this regard, this might be reflected in altered growth and reproductive output of red compared to green individuals.
Both phenotypes displayed similar photosynthetic performance indices before and after the winter red period, yet reds suffered a considerable drop in this parameter concomitant with anthocyanin accumulation. This photosynthetic inferiority was irregularly linked to growth, since red plants produced fewer new leaves during the following spring, yet shoot relative growth rate was higher. Moreover both phenotypes displayed similar flower numbers, pollination success and seed yield, mass and germinability.
As judged by the similar final reproductive output, vulnerability to the winter stress does not render the red phenotype less fit, nor anthocyanin accumulation render it more fit. Moreover, the photosynthetic inferiority of the red phenotype, although linked to slightly reduced leaf number, it was not limiting for reproductive effort and success.
Regardless of function, winter leaf redness in C. creticus may indicate photosynthetically weak individuals. However. neither a fitness cost nor benefit of anthocyanins can inferred in this system.

• 出版日期2010-1