Estimation of Dry Matter Intake by Grazing Comisana Ewes

Veterinary Research Communications -     

Image changes in chlorophyll fluorescence of cucumber leaves in response to iron deficiency and resupply

Iron (Fe) is an essential element for plants and its deficiency causes decrease not only in the photosynthetic rate but also in the actual photosystem II efficiency at steady‐state photosynthesis. The aim of this work was to determine the effect of Fe deficiency in plants of Cucumis sativus (L.) in two different experimental conditions. In the first experiment, plants were grown with or without Fe for 7 d. After 7 d, Fe‐deficient plants were resupplied with Fe and sampled after 12 h and 48 h. In the second experiment, plants were grown with Fe in the nutrient solution for 3 d and after this period, Fe was withdrawn and plants sampled after 3 and 6 d. Iron and chlorophyll (Chl) concentration and Chl‐fluorescence imaging were measured. In cucumber leaves subjected to Fe deficiency, fluorescence imaging of Chl a evidenced spatial changes on leaf lamina. Following Fe deficiency both after 7 d (Exp. 1) or 6 d (Exp. 2) leaves showed a slight, nonsignificant decrease in F_v/F_m ratio. However Chl‐fluorescence parameters determined in light conditions showed significant changes which indicate an alteration in the photosynthetic process. Surprisingly, the effect of Fe deficiency was more pronounced in leaves of plant of Exp. 2 as compared to those that had grown in complete absence of Fe (Exp. 1). In the latter case down‐regulated mechanisms preserved leaves from irreversible photoinhibition leading to complete recovery when plants were resupplied with the microelement.     

Prophylactic use of a lyophilized platelet product for rhinoscopic diagnosis and treatment of sinonasal aspergillosis in a dog with a P2Y12 platelet receptor mutation

Objective

To describe the periprocedural use of a lyophilized platelet product during rhinoscopic diagnosis and treatment of sinonasal aspergillosis in a Greater Swiss Mountain Dog with a P2Y12 platelet receptor disorder.

Case Summary

After the development of severe epistaxis, a Greater Swiss Mountain Dog was diagnosed with thrombopathia secondary to a P2Y12 receptor gene mutation. Concurrent primary nasal disease was also suspected due to persistent mucopurulent nasal discharge. One month after the initial presentation for epistaxis, the dog was readmitted for workup of nasal disease. Computed tomography of the head showed turbinate lysis and regional lymphadenopathy. Because of concern for a high risk of bleeding in a thrombopathic patient subjected to rhinoscopy and nasal biopsies, a lyophilized platelet product was administered prior to the procedure. Rhinoscopic exam revealed fungal plaques consistent with Aspergillus spp. that were later confirmed on fungal culture to be Aspergillus fumigatus. Rhinoscopic biopsies were performed as well as debridement of the fungal plaques, followed by topical administration of clotrimazole solution. Bleeding was minimal during and after the procedure, and the dog recovered uneventfully.

New or Unique Information Provided

This is the first report of the prophylactic use of lyophilized platelets in a thrombopathic patient undergoing an invasive procedure with potential for significant hemorrhage. Minimal bleeding occurred during the procedure, suggesting that lyophilized platelets could be used for the prevention of bleeding in thrombopathic patients undergoing invasive procedures.     

Oxidative stress responses and root lignification induced by Fe deficiency conditions in pear and quince genotypes

We analysed Pyrus communis cv. Conference and Cydonia oblonga BA29, differently tolerant to lime-induced chlorosis, to identify the key mechanisms involved in their different performance under Fe deficiency induced by the absence of Fe (-Fe) or by the presence of bicarbonate (+FeBic). Under our experimental conditions, a decrease in root elongation was observed in BA29 under bicarbonate supply. Superoxide dismutase (SOD) and peroxidase (POD) activities were analysed and the relative isoforms were detected by native electrophoresis. The data obtained for both genotypes under -Fe and for BA29 +FeBic suggest the occurrence of overproduction of reactive oxygen species (ROS) and, at the same time, of a scarce capacity to detoxify them. The detection of ROS (O(2)(-) and H(2)O(2)) through histochemical localization supports these results and suggests that they could account for the modifications of mechanical properties of the cell wall during stress adaptation. On the other hand, in the cv. Conference +FeBic, an increase in non-specific POD activity was detected, confirming its higher level of protection in particular against H(2)O(2) accumulation. Peroxidases involved in lignification were assayed and histochemical analysis was performed. The results suggest that only in BA29 under bicarbonate supply can the presence of ROS in root apoplast be correlated with lignin deposits in external layers and in endodermis as a consequence of the shift of PODs towards a lignification role. We suggest that in BA29 the decrease in root growth could impair mineral nutrition, generating susceptibility to calcareous soils. In the cv. Conference, the allocation of new biomass to the root system could improve soil exploration and consequently Fe uptake.     

Comparison of three pea cultivars (Pisum sativum) regarding their responses to direct and bicarbonate-induced iron deficiency

The aim of this work was to explore leaf characteristics underlining the difference in the sensitivity of pea cultivars (cv. Kelvedon, Douce and Lincoln) to Fe deficiency. Plants were grown in a greenhouse under controlled conditions in continuously aerated solution. Three treatments were used: 30 μM Fe (+Fe), 0 μM Fe (−Fe); direct deficiency and 30 μM Fe + 10 mM NaHCO₃ (+Fe+Bic); indirect deficiency for 12 days. Growth parameters, iron status, potassium content, chlorophyll fluorescence and photosynthetic capacity were studied. Our results showed that Fe deficiency led to a significant decrease of chlorophyll index (SPAD readings) and bivalent iron content in all Pisum sativum cultivars. The lower reduction was observed in Fe-deficient plants of Kelvedon and Douce. In addition, shoot length and whole plant dry weight were not affected by Fe deficiency in the latter cultivars. Both tolerant cultivars showed higher accumulation of potassium content in their leaves compared with the sensitive one. Moreover, both chlorophyll fluorescence ratios (F_v/F_m and F_v/F₀) were significantly decreased in all cultivars under both Fe deficiency treatments. The photosynthetic electron transport activity was reduced in the sensitive cultivar, especially in the absence of iron. The adverse effect of bicarbonate-induced Fe deficiency on the above mentioned parameters were more pronounced than that of the direct one. The capacity of both tolerant cultivars to preserve adequate chlorophyll synthesis, photosynthetic capacity and plant growth under iron-limiting conditions is related to the suitable nutrition of their leaves in ferrous iron, due to (at least partially) their higher potassium content.