Growth and photosynthetic responses to zinc stress of an invasive cordgrass, Spartina densiflora

Abstract

Spartina densiflora Brongn. is found in coastal marshes of southwest Spain, growing over sediments containing 100-4800 ppm Zn. A glasshouse experiment was designed to investigate the effect of Zn from 0 to 100 mmol.l(-1) on the growth and photosynthetic apparatus of S. densiflora, by measuring relative growth rate, leaf elongation rate, number of tillers, height of tillers, chlorophyll fluorescence parameters, gas exchange and photosynthetic pigment concentrations. We also determined total ash, Zn, calcium, magnesium and phosphorus concentrations, and the C/N ratio. At 100 mmol.l(-1) Zn, S. densiflora showed a 48% biomass reduction after 1 month of treatment. Long-term effects of Zn on growth of S. densiflora consisted mainly of variations in net photosynthesis. Modification of the Zn/Mg ratio was linked to a strong decrease in RuBP carboxylase (Zn was favoured in local competition with Mg, so that the affinity of RuBisCO for CO(2) decreased), oxygenase activity of RuBisCO acting as a substitute for the photosynthetic function. Also, Zn had a marked overall effect on the photochemical (PSII) apparatus and the synthesis of photosynthetic pigments. However, the results indicate that S. densiflora is capable of tolerating very high and continued exposure to Zn, as this species lowers the translocation of Zn from the nutrient solution to roots and controls Zn ion transport into leaves. Therefore, S. densiflora could be useful in the phytostabilization of soils.

Physiological, biochemical and mineral dimensions of green beangenotypes depending on Zn priming and salinity

“…Tavori et al (2004) also reported that NaCl concentration in high amounts decreased Ca accumulation in the stem and the leaves of chickpea. Mateos-Naranjo et al (2008) found that Zn reduced the tissue Ca concentration of S. densiflora.…”

Synergic effect of salinity and zinc stress on growth and photosynthetic responses of the cordgrass, Spartina densiflora

“…During this period the entire solutions were changed on a 5 d basis. Zn and NaCl concentrations were chosen to cover variations recorded by Mateos-Naranjo et al (2008 a and b , respectively) in the salt marshes of Odiel River where S. densiflora occurs.…”

“…Cambrollé et al (2008) found that heavy metals (including Zn) accumulated at different rates in S. densiflora tissues and around its roots, concluding that these species could be used for phytoremediation and phytostabilization of estuarine sediments. Mateos-Naranjo et al (2008 a ) studied the effect of Zn on the growth and photosynthetic apparatus of S. densiflora in a glasshouse experiment, but no attention was paid to the interaction with salt.…”

Morphology, photosynthesis, and internal structure alterations in field apple leaves under hidden and acute zinc deficiency

“…Fluorescence parameters were determined synchronously with the gas exchange measurements in the field using a portable pulsemodulated fluorometer (FMS-2, Hansatech, England) under natural conditions according to Mateos-Naranjo et al (2008). Tested leaves were kept in the dark for 30 min before measurement.…”