Photosynthesis and growth of young grapevines intercropped with native grasses in soils contaminated with copper.

Abstract High copper (Cu) contents in vineyard soils due to long-term foliage-defense program based on Cu-containing fungicides may cause physiological and nutritional disorders in young grapevines, limiting plant growth and in some cases also compromising plant survival. This problem is particularly evident in viticultural areas of southern Brazil. Therefore, the study aimed to assess if the intercropping of grapevines with native grasses of southern Brazil can contribute to limit the soil Cu availability and thus the onset of toxicity symptoms (i.e., impairment of photosynthetic and growth parameters). In order to do this, we collected soil samples in the natural grassland of the Pampa Biome (southern Brazil). The samples were air-dried, the acidity, phosphorus and potassium levels were corrected and the samples were consequently incubated. We used three Cu levels ? control (i.e., no Cu addition), 40 and 80 mg Cu kg-1. Such Cu levels are normally found in vineyard soils of the region. The experimental design was completely randomized with three replications. At each Cu level, we set up three combinations of monocropping (Grapevine), and intercropping with Paspalum plicatulum Michx. (Grapevine + Paspalum plicatulum) and Axonopus affinis Chase (Grapevine + Axonopus affinis). In the intercropped treatments, two grass seedlings were transplanted into each experimental unit, 35 days before transplanting the grapevines. The experiment was conducted for 70 days. At 41 days after transplanting the grapevines, gas exchange (IRGA) was measured. At 70 days, plant height and total dry matter yield were determined and the relative growth rate was quantified. The addition of Cu caused phytotoxicity in the single crop (Grapevine), reducing photosynthetic carbon assimilation and plant growth. The cultivation of young grapevines intercropped with native grasses, especially Paspalum plicatulum Michx., promoted the growth of the grapevines in the control soil as well as in the moderately Cu-contaminated soils. This indicates that maintaining native vegetation in young vineyards can reduce Cu toxicity to transplanted grapevines.Made available in DSpace on 2019-04-12T00:43:10Z (GMT). No. of bitstreams: 1 Photosynthesisandgrowthofyounggrapevines.pdf: 353474 bytes, checksum: cd23232aad4150f46391fa7a2b8b8b47 (MD5) Previous issue date: 2018bitstream/item/190112/1/Photosynthesis-and-growth-of-young-grapevines.pd

The interaction of high copper and zinc doses in acid soil changes the physiological state and development of the root system in young grapevines (Vitis vinifera).

Old vineyards may present high copper (Cu) content in the soil due to the frequent application of Bordeaux fungicide to control leaf fungal diseases. Thus, many wine makers replace copper fungicides by those made of zinc (Zn) and it leads to the accumulation of these two elements in vineyard soils, fact that may potentiate the occurrence of physiological disorders and morphological changes in the plant root system. The aim of the current study was to assess the effects of high Cu and Zn contents in a sandy acid soil on the physiological state and development of the root system in young grapevines. The soil was taken from a vineyard from Southern Brazil, and then it was sieved and had its acidity and P and K contents corrected. Next, the soil was subjected to the application of 0 and 120 mg Cu kg−1; each one of these doses was added with 0, 120 and 240 mg Zn kg−1, thus totaling six treatments. After the treatments were added to the soil samples, 2.4 kg of soil was stored in rizoboxtype containers. One young grapevine plant was transplanted to each box. The transplanted plants were cultivated for 60 days in greenhouse. The accumulation of root and shoot dry matter was set after the experimental period, as well as the Cu and Zn contents in the roots and shoot, the root system morphology, the chlorophyll a fluorescence, the photosynthetic pigments, the gas exchanges and the superoxide dismutase enzyme activity (SOD). Young grapevines presented mechanisms to tolerate high Cu and Zn concentrations in the soil, mainly through the retention of such metals in their roots to diminish translocation to the shoot. However, the highest Cu and Zn doses led to grapevine plant growth decrease, to gas exchange alterations and to photochemical efficiency reduction associated with photosynthetic pigment decrease and to non-photochemical energy dissipation increase. Moreover, the SOD activity was greater in intermediate Zn doses, thus indicating antioxidant system activation. Thus, the combination between high Cu and Zn concentrations in vineyard soils will enable minimizing the toxic effects of these metals to young grapevines cultivated in these soils.Made available in DSpace on 2019-01-11T00:09:13Z (GMT). No. of bitstreams: 1 Theinteractionofhighcopperandzincdosesinacidsoil.pdf: 215749 bytes, checksum: 5ad3c73c02490620635b4493f98263df (MD5) Previous issue date: 2019-01-09bitstream/item/190117/1/The-interaction-of-high-copper-and-zinc-doses-in-acid-soil.pd

The interaction of high copper and zinc doses in acid soil changes the physiological state and development of the root system in young grapevines (Vitis vinifera).

Old vineyards may present high copper (Cu) content in the soil due to the frequent application of Bordeaux fungicide to control leaf fungal diseases. Thus, many wine makers replace copper fungicides by those made of zinc (Zn) and it leads to the accumulation of these two elements in vineyard soils, fact that may potentiate the occurrence of physiological disorders and morphological changes in the plant root system. The aim of the current study was to assess the effects of high Cu and Zn contents in a sandy acid soil on the physiological state and development of the root system in young grapevines. The soil was taken from a vineyard from Southern Brazil, and then it was sieved and had its acidity and P and K contents corrected. Next, the soil was subjected to the application of 0 and 120 mg Cu kg?1 ; each one of these doses was added with 0, 120 and 240 mg Zn kg?1 , thus totaling six treatments. After the treatments were added to the soil samples, 2.4 kg of soil was stored in rizoboxtype containers. One young grapevine plant was transplanted to each box. The transplanted plants were cultivated for 60 days in greenhouse. The accumulation of root and shoot dry matter was set after the experimental period, as well as the Cu and Zn contents in the roots and shoot, the root system morphology, the chlorophyll a fluorescence, the photosynthetic pigments, the gas exchanges and the superoxide dismutase enzyme activity (SOD). Young grapevines presented mechanisms to tolerate high Cu and Zn concentrations in the soil, mainly through the retention of such metals in their roots to diminish translocation to the shoot. However, the highest Cu and Zn doses led to grapevine plant growth decrease, to gas exchange alterations and to photochemical efficiency reduction associated with photosynthetic pigment decrease and to non-photochemical energy dissipation increase. Moreover, the SOD activity was greater in intermediate Zn doses, thus indicating antioxidant system activation. Thus, the combination between high Cu and Zn concentrations in vineyard soils will enable minimizing the toxic effects of these metals to young grapevines cultivated in these soils. Keywords: Vineyard soils Gas exchange Chlorophyll fluorescence Root system Photosynthetic pigments Heavy metal

The effect of a glyphosate-based herbicide on acetylcholinesterase (AChE) activity, oxidative stress, and antioxidant status in freshwater amphipod: Gammarus pulex (Crustacean)

This study had determined the effect of glyphosate-based herbicide (GBH) on acetylcholinesterase (AChE) enzyme activity, oxidative stress, and antioxidant status in Gammarus pulex. Firstly, the 96-h LC50 value of glyphosate on G. pulex was determined and calculated as 403 μg/L. Subsequently, the organisms were exposed to sub-lethal concentrations (10, 20, and 40 μg/L) of the determined GHB for 24 and 96 h. The samples were taken from control and GBH-treated groups at 24 and 96 h of study and analysed to determine the malondialdehyde (MDA) and reduced glutathione (GSH) levels, the AChE, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) enzyme activities. In the G. pulex exposed to GBH for 24 and 96 h, the MDA level increased significantly (p < 0.05). The GSH level, the AChE, the CAT, and the GPx activities decreased compared with the control group (p < 0.05). G. pulex exposure to GBH for 24 h showed a temporary reduction in the SOD. GBH exposure led to oxidative stress in the G. pulex as well as affected the cholinergic system of the organism. These results indicated that the parameters measured may be important indicators of herbicide contamination in G. pulex