TY  - JOUR
AU  - Greer, D.H.
AU  - Thorpe, M.R.
TI  - Leaf photosynthetic and solar-tracking responses of mallow, Malva parviflora, to photon flux density
JO  - Plant physiology and biochemistry
VL  - 47
SN  - 0981-9428
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - PreJuSER-8362
SP  - 946 - 953
PY  - 2009
N1  - We thank Wayne Scott for technical assistance for this project. The study was also technically supported by Evert Van Thoor while on an Internship from Wageningen University and Research Centre for a Masters degree in Agricultural Engineering. We also thank SAS Australia for their generous support to the senior author for supplying software.
AB  - Malva parviflora L. (mallow) is a species that occupies high-light habitats as a weedy invader in orchards and vineyards. Species of the Malvaceae are known to solar track and anecdotal evidence suggests this species may also. How M. parviflora responds physiologically to light in comparison with other species within the Malvaceae remains unknown. Tracking and photosynthetic responses to photon flux density (PFD) were evaluated on plants grown in greenhouse conditions. Tracking ability was assessed in the growth conditions and by exposing leaves to specific light intensities and measuring changes in the angle of the leaf plane. Light responses were also determined by photosynthesis and chlorophyll fluorescence. Leaves followed a heliotropic response which was highly PFD-dependent, with tracking rates increasing in a curvilinear pattern. Maximum tracking rates were up to 20 degrees h(-1) and saturated for light above 1,300 micromol (photons) m(-2) s(-1). This high-light saturation, both for tracking (much higher than the other species), and for photosynthesis, confirmed mallow as a high-light demanding species. Further, because there was no photoinhibition, the leaves could capture the potential of an increased carbon gain in higher irradiance by resorting to solar tracking. Modelling suggested the tracking response could increase the annual carbon gain by as much as 25% compared with leaves that do not track the sun. The various leaf attributes associated with solar tracking, therefore, help to account for the success of this species as a weed in many locations worldwide.
KW  - Carbon: metabolism
KW  - Chlorophyll: chemistry
KW  - Chlorophyll: metabolism
KW  - Ecosystem
KW  - Fluorescence
KW  - Malva: metabolism
KW  - Malva: physiology
KW  - Models, Biological
KW  - Photons
KW  - Photosynthesis: radiation effects
KW  - Plant Leaves: metabolism
KW  - Plant Leaves: physiology
KW  - Seasons
KW  - Sunlight
KW  - Time Factors
KW  - Chlorophyll (NLM Chemicals)
KW  - Carbon (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:19576789
UR  - <Go to ISI:>//WOS:000269586400011
DO  - DOI:10.1016/j.plaphy.2009.06.002
UR  - https://juser.fz-juelich.de/record/8362
ER  -