Evaluating wild grapevine tolerance to copper toxicity

We evaluate copper tolerance and accumulation in Vitis vinifera ssp. sylvestris in populations from a copper contaminated site and an uncontaminated site, and in the grapevine rootstock "41B", investigating the effects of copper (0-23. mM) on growth, photosynthetic performance and mineral nutrient content. The highest Cu treatment induced nutrient imbalances and inhibited photosynthetic function, causing a drastic reduction in growth in the three study plants. Effective concentration was higher than 23. mM Cu in the wild grapevines and around 9. mM in the "41B" plants. The wild grapevine accessions studied controlled root Cu concentration more efficiently than is the case with the "41B" rootstock and must be considered Cu-tolerant. Wild grapevines from the Cu-contaminated site present certain physiological characteristics that make them relatively more suitable for exploitation in the genetic improvement of vines against conditions of excess Cu, compared to wild grapevine populations from uncontaminated site

Assessing the effect of copper on growth, copper accumulation and physiological responses of grazing species Atriplex halimus: Ecotoxicological implications

Tolerance of plants to elevated concentrations of heavy metals in growth media and in its tissues leads to high degrees of metal bioaccumulation, which may pose a risk for humans and animals alike. Therefore, bio-accumulating plants need thorough evaluation from an environmental health point of view. A glasshouse experiment concerning the xerohalophyte Atriplex halimus was carried out to determine its tolerance and capacity to accumulate copper. We investigated the effect of Cu from 0 to 30mmoll-1 on the growth, photosynthetic apparatus and nutrient uptake of A. halimus by measuring gas exchange, chlorophyll fluorescence and photoinhibition. We also determined total Cu, sodium, potassium, magnesium, phosphorous, and nitrogen content in the plant. Our results indicated that A. halimus presented a high resistance to Cu-induced stress, since the plants were able to survive at concentrations higher than 15mmoll-1 Cu. However, this capacity was not reflected in its ability to accumulate and tolerate greater amounts of Cu in its tissues, since clear phytotoxicity symptoms were detected at tissue concentrations greater than 38mgkg-1 Cu. Thus, Cu increment caused a reduction in A. halimus growth, which was related to a decrease in net photosynthetic rate. This reduction was associated with the adverse effect of Cu on the photochemical apparatus and the reduction in the absorption of essential nutrients. The high resistance of A. halimus was largely related with the capacity of this species to avoid the absorption of great amounts of Cu. For all the above reasons, A. halimus could have the characteristics of a Cu-exclusion plant.Peer Reviewe

Physiological responses to soil lime in wild grapevine (Vitis vinifera ssp. sylvestris)

Lime-induced chlorosis is a widespread nutritional disorder affecting grapevines cultivated in calcareous soils. A greenhouse experiment was conducted to investigate the response of Vitis vinifera ssp. sylvestris to soil lime by evaluating the effects of a range of soil CaCO3 contents (0-60%) on plant growth, nutrient content (iron, potassium, nitrogen and phosphorus) and photosynthetic performance (gas exchange, chlorophyll fluorescence parameters and photosynthetic pigments). The highest soil CaCO3 concentration induced nutrient imbalances and significantly inhibited photosynthetic function, causing a reduction in carbon gain and consequently, a drastic growth reduction and high mortality. However, all the plants survived external CaCO3 contents of up to 40%, and reduction in growth at 20% CaCO3 was slightly lower than that recorded in several previously studied lime-tolerant varieties of grapevine. Plants grown at 20% CaCO3 maintained net photosynthesis values of around 6μmolm-2s-1, a similar chlorophyll content to that of the control plants and dawn Fv/Fm values close to the optimal values for unstressed plants. Up to the 40% CaCO3 treatment, the study species was capable of maintaining Fe uptake by the roots and translocation to leaves, while controlling the nutritional status of N and P. Our study indicates that the studied population of V. vinifera ssp. sylvestris could provide a source of genetic diversity for lime tolerance improvement in grapevine.CSIC 201140E12

HEAVY METALS IN VINEYARDS AND ORCHARD SOILS

The application of foliar fungicides in vineyards and orchards can increase soil concentration of heavy metals such as copper (Cu) and zinc (Zn), up to the toxicity threshold for fruit trees and cover crops. However, some agronomic practices, such as liming, addition of organic fertilizers, cultivation of soil cover crops and inoculation of young plants with arbuscular mycorrhizal fungi can decrease the availability and the potential of heavy metal toxicity to fruit trees. This review aims to compile and present information about the effects of increasing concentrations of heavy metals, especially Cu and Zn, on soils cultivated with fruit trees and provides some agronomic practices of remediation. Information about the sources of heavy metals found in soils cultivated with fruit trees are presented; mechanisms of absorption, transport, accumulation and potential toxicity to plants are described