Evolutionary Developmental Biology (Evo-Devo)
Stanfield, Ryan , Ewers, Frank , Bobich, Edward .
The Physiological Significance of Plant Cystoliths; Can These Structures Sequester the Heavy Metal Cadmium?
Cystoliths are calcium carbonate deposits in the leaves of a select few plant families. Though helping to provide anatomical evidence for phylogenetic relationships, the physiological function of the cystolith has remained elusive. Other forms of calcium (Ca) deposits, for instance in tobacco leaves, serve to excrete cadmium (Cd) in the presence of excess Ca, helping to prevent some heavy metal toxicity. Further, traces of heavy metals have been reported to occur within cystoliths. The purpose of this study was to determine if one of the possible functions of the cystolith is for the sequestration of heavy metals, such as Cd. If storage is occurring, does it confer a higher resistance to metal toxicity in the presence of excess Ca, in comparison to non-cystolith producing plants? Plants of the family Acanthaceae were grown in tissue culture or from cuttings then transferred to media containing varying amounts of Ca and or Cd. One of the species that was selected does not produce cystoliths, and it was used as a control. An extraction protocol was refined, and then used to separate cystoliths from the rest of the leaf. Cystolith, leaf, and root samples were then analyzed using ICP-MS to quantify Cd content. Cystoliths were measured for density, length, and width. Plant health indicators such as photosynthetic florescence and stomatal conductance were also measured. Trace amounts of Cd were confirmed to be in cystoliths. Calcium appeared to help buffer against Cd toxicity for both cystolith and non-cystolith producing plants, but more so for cystolith producing plants. In this experiment, the cystoliths may have been more important for managing excess Ca, which could then be used to displace Cd ions.
1 - California State Polytechnic University, Biological Sciences, 3801 West Temple Avenue, Pomona, CA, 91768, USA
2 - California State Polytechnic University, Pomona, Office Of Research, 3801 West Temple Avenue, Pomona, CA, 91768, USA
3 - 1261 W. 15th St., Upland, CA, 91786, USA
Presentation Type: Oral Paper:Papers for Topics
Candidate for Awards:Katherine Esau Award,Maynard F. Moseley Award