Biscutella update: thallium and metal tolerance tests

The following work was presented at ICOBTE 2011 as a poster.

Thallium is a toxic heavy metal which pollution can derive from anthropogenic or pedogeochemical sources.

In our previous analysis we reported a presence of Biscutella laevigata subsp. laevigata in the former mining area of Cave del Predil, Tarvisio (Italy) (Fellet et al., 2011). In those specimens the average shoot Tl concentration was above the threshold for hyperaccumulation (> 1,000 ppm).

Biscutella laevigata subsp. laevigata on maining tails at Cave del Predil (Italy)

Plantlets from three geographically distant metallicolous [Cave del Predil (Cap), I and Ganges (Gan), F) and nonmetallicolous (Codroipo (Cod), I] B. laevigata subsp. laevigata populations were tested for Tl tolerance and accumulation for 8 days at increasing concentrations of Tl. You can see in the following picture how the tollerant populations develop more roots (white filaments) comparing to the non tolerant at 10 ppm Tl in solution.

The main findings were:

• The Cap population had the highest indices of tolerance in root elongation test and Tl concentration in shoots (up to 28,746 mg kg-1) and roots (up to 16,086 mg kg-1);
• A hyperacumulator Tl population of B. l. subsp. laevigata differentiation occurred in Cave del Predil;
• The Tl tolerance and accumulation is probable constitutive and adaptive;
• A phytomining of Tl by Cap population is a promising technique for soil remediation and for obtaining this rare, required and expensive metal (5,930 $ Kg^-1 in 2010).

As Tl is not a redox metal therefore cannot yield hydroxyl radicals, it may cause oxidative stress in plants by disturbing the Photosystem II that will lead to greater production of Reactive oxygen species in nontolerant plants. Further studies on oxidative stress are on-going in Free University of Amsterdam.

Amazing! AnOVa three factors for excel 2007!

AnOVa (Analysis Of Variance) provides a statistical test of whether or not the means of several groups are all equal, and therefore generalizes t-test to more than two groups. In one way AnOVa you compare only one factor while in two or more ways you compare means of several groups through many factors. For example one can be interested if there is any difference between the measured variable (the dependent variable) in several populations (first factor or way - i.e. the first indipendent variable) through different toxic concentrations (second factor or way - i.e. the second indipendent variable).

Several programs can compute AnOVa but most of them are not free (SPSS, Statistica, SAS). On the other hand Past is a very useful free statistic package. However this program can only compute AnOVa till two factors. Excel doesn't provide a full statistic package for AnOVa - only for one way.

The file AnOVa for excel its my new creation and it is very useful expecially if the users can not access not free proprietary software and need three factors AnOVa.

The output of my AnOVa for excel

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Phytostabilization of Cu by green covering species in organic vineyards

Dr. Mattiello is working in a organic vineyards near Cormons (UD, Italy)

This study is a part of a bigger project named Multifarm.

Differential tolerance to thallium of Biscutella population in hydroponics

Effects of different concentration of Tl on plantlets in hydroponics

We are currently developing a new method for measuring the new root growth in two dimension hydroponics system with staining black method. You can see the development of the experiment in this "nice" improvised video:

The photo of the final experimental plot is shown:

2D Hydroponic culture

Stained black roots system

For further experiments, in order to enable the measurement of new root growth of Biscutella laevigata subsp. laevigata in hydroponic, we set an experiment plot for controlling the accumulation of Tl and Cu in normal and in stained black roots replicates. At the start of the tests, the roots were stained black by active charcoal.

Hydroponic plot experiment

After ICP-OES analysis the results were elaborated by standard t-test statistics. Our results are in according with Schat and Ten Bookum (1992) and proved staining black roots with activated charcoal is non-invasive.

A particular population of a pseudometallophyte

Our recent work on ecological and genetical data demonstrates a interspecific variation in the pseudometallophyte Biscutella laevigata subsp. laevigata from Cap population. The individuals from Cap population have particular properties in hyperaccumulation of heavy metals. It seems that Biscutella laevigata subsp. laevigata belong to the class B of the following figure. (Fellet et al., 2010)

Identification of sunflower species and interspecific hybrids through DNA barcodes

Sunflower (Helianthus annuus)	Helianthus annuus, H. argophyllus, H. debilis subspecies, H. tuberosus and interspecific hybrids were characterized using five proposed DNA barcoding loci. Interspecific variability due to SNPs and indels was sufficient for the identification of H. debilis and H. tuberosus. On the other hand, H. annuus and H. argophyllus presented no interspecific differences.
However these two species presented diverse haplotype compositions. Moreover our results showed a clear usefulness of ITS and trnH-psbA in identifying the origins of various hybrids. (Pošćić and Vischi, 2010)
Electropherogram comparison of ITS sequences