Citrus allergy from pollen to clinical symptoms

Allergy to citrus fruits is often associated with pollinosis and sensitization to other plants due to a phenomenon of cross-reactivity. The aims of the present study were to highlight the cross-reactivity among citrus and the major allergenic pollens/fruits, throughout clinical and molecular investigations, and to evaluate the sensitization frequency to citrus fruits in a population of children and adults with pollinosis. We found a relevant percentage of sensitisation (39%) to citrus fruits in the patients recruited and in all of them the IgE-mediated mechanism has been confirmed by the positive response to the prick-to-prick test. RT-PCR experiments showed the expression of Cit s 1, Cit s 3 and a profilin isoform, already described in apple, also in Citrus clementine pollen. Data of multiple sequence alignments demonstrated that Citrus allergens shared high percentage identity values with other clinically relevant species (i.e. Triticum aestivum, Malus domestica), confirming the possible cross-allergenicity citrus/grasses and citrus/apple. Finally, a novelty of the present work has been the expression of two phospholipaseA2 isoforms (PLA2 \u3b1 and \u3b2) in Citrus as well as in Triticum pollens; being PLA2 able to generate pro-inflammatory factors, this enzyme could participate in the activation of the allergenic inflammatory cascade

Effect of complementary irrigation on yield components and alternate bearing of a traditional olive orchard in semi-arid conditions

Traditional olive orchards are usually not irrigated in the Mediterranean basin, but at those latitudes, the yearly rainfall is frequently insufficient to support equilibrated vegetative growth and high fruit and oil production. This three-year field study investigated the effect of complementary irrigation on olive tree vegetative growth, fruit and oil yield during a biennial alternate bearing cycle in a traditional grove under semi-arid conditions. Adult olive trees (Olea europaea L. cv. Nabali Baladi) were subjected to complementary irrigation in 2011 and 2012 ('on' and 'off' years, respectively) with 6, 10, 15 or 20 m3 of water per tree per season, which corresponded to 14.2%, 23.8%, 35.7% and 47.6% of the whole seasonal evapotranspiration (42 m3 of water per year), respectively. Rain-fed trees were used as control. In 2013, no complementary irrigation was supplied, and any residual effects on the yield components were determined. Results showed that none of the irrigation regimes affected vegetative growth, or olive fruit size (mesocarp and endocarp), as fresh and dry weights. The fruit and oil yield per tree increased compared to the rain-fed conditions only when the threshold of 15 m3 was exceeded, thus inducing a higher crop load compared to the rain-fed control during the 'off' and even further during the 'on' year. No residual effects were registered in 2013. The study showed that complementary irrigation of at least 35% of the seasonal water requirement can produce remarkable positive effects on fruit yield especially during 'on' bearing years

Water deficit-induced changes in mesocarp cellular processes and the relationship between mesocarp and endocarp during olive fruit development

A field experiment was conducted during two consecutive growing seasons to determine and quantify the growth response of the olive (Olea europaea L. cv. Leccino) fruit and of its component tissues to tree water status. Pre-dawn leaf water potential (Ψw) and fruit volume were measured at about weekly intervals, and fresh weight (FW) and dry weight (DW) of the fruit tissues at 15, 20 and 21 weeks after full bloom (AFB). Fruit anatomical sections were prepared at 8, 15 and 21 weeks AFB for area determinations and cell counts. Fruit volume of the well-watered trees (average Ψw = −0.97 MPa) increased rapidly and reached the greatest final size, that from the most stressed (average Ψw = −2.81 MPa) grew most slowly and were smallest. In general, equatorial transverse areas of the mesocarp increased with increasing Ψw, and this response was more evident at 21 than at 15 weeks AFB. By 21 weeks AFB, the mesocarp of the well-watered trees reached values more than three times higher than those measured at 8 weeks AFB. The endocarp FW and DW did not increase between 15 and 21 weeks AFB. Within each sampling date the endocarp area, FW and DW responded weakly to Ψw. The mesocarp-to-endocarp ratio (FW and DW) increased from 15 to 21 weeks AFB regardless of water status, mainly due to the mesocarp growth. In both years at 20 and 21 weeks AFB, low values of the mesocarp-to-endocarp ratio were found with Ψw below −2.5 MPa. Within the mesocarp, cell size was more responsive to water deficit than to cell number. At 8 weeks AFB, the number of cells in the mesocarp was unaffected by tree water deficit, whereas cell size decreased, although slightly, in fruits sampled from trees in which Ψw was < −3.0 MPa. At 21 weeks AFB, cell size showed a linear decrease with increasing level of water deficit, whereas the number of cells at 21 weeks AFB decreased as the Ψw decreased below −2.5 MPa and seemed unaffected above that range. Overall, the results clarify the complexity of the water-induced response of mesocarp and endocarp growth and cellular processes of olive fruits.This work was supported by the Spanish Ministry of Education projects AGL2005- 00930 and AGL2008-02570

PRODUCTIVITY OF OLIVE TREES WITH DIFFERENT WATER STATUS AND CROP LOAD

A field experiment was conducted over two growing seasons to determine the combined effect of crop load and irrigation on yield components of olive trees (Olea europaea L. ‘Leccino’) planted at 6 m 3.8 m in a sandy-clay soil. Different crop loads were established by manual thinning of fruits. Drip irrigation was managed to maintain pre-dawn leaf water-potentials (PLWP) within the following ranges: (i) higher than –1.1 MPa (FI; fully irrigated); (ii) between –1.0 and –3.3 MPa (DI; deficit irrigated); or (iii) below –1.2 MPa, but not lower than –4.2 MPa (SI; severe deficit irrigated).The irrigation period lasted from 6 – 16 weeks after full bloom (AFB) in 2003, and from 5 – 19 weeks AFB in 2004. In 2003, full bloom was on 26 May; in 2004, it was on 3 June. Neither irrigation regime nor crop load affected flowering or flower quality the following Spring. The combined fruit yields [on a fresh weight (FW) basis] over both years in SI and DI trees were 49.0% and 81.6% of FI trees, respectively.The oil yields of SI and DI trees were 52.5% and 81.2% of FI trees, respectively. Fruit FWs in FI trees were greater than those of DI or SI trees at 8 weeks AFB.At harvest, FI trees bore the largest fruits, and SI trees the smallest fruits. The FWs of individual fruits at harvest in the FI and DI treatments decreased as crop load increased, but no such relationship was apparent for SI trees. The oil content of the mesocarp increased as PLWP increased from approx. –3.5 MPa to –1.5 MPa.The oil content of FI trees at harvest decreased from 53.1% to 45.7% dry weight as fresh fruit yield increased from 5 – 25 kg dm–2 trunk crosssectional area. However, crop load did not have any effect on the oil content of the mesocarp in DI trees. Fruit maturation was delayed by irrigation. Maturation index also decreased (indicating delayed maturation) as the crop load on FI or DI trees increased, but did not vary with crop level in SI trees

Productivity of olive trees with different water status and crop load

A field experiment was conducted over two growing seasons to determine the combined effect of crop load and irrigation on yield components of olive trees (Olea europaea L. ‘Leccino’) planted at 6 m 3.8 m in a sandy-clay soil. Different crop loads were established by manual thinning of fruits. Drip irrigation was managed to maintain pre-dawn leaf water-potentials (PLWP) within the following ranges: (i) higher than –1.1 MPa (FI; fully irrigated); (ii) between –1.0 and –3.3 MPa (DI; deficit irrigated); or (iii) below –1.2 MPa, but not lower than –4.2 MPa (SI; severe deficit irrigated). The irrigation period lasted from 6 – 16 weeks after full bloom (AFB) in 2003, and from 5 – 19 weeks AFB in 2004. In 2003, full bloom was on 26 May; in 2004, it was on 3 June. Neither irrigation regime nor crop load affected flowering or flower quality the following Spring. The combined fruit yields [on a fresh weight (FW) basis] over both years in SI and DI trees were 49.0% and 81.6% of FI trees, respectively. The oil yields of SI and DI trees were 52.5% and 81.2% of FI trees, respectively. Fruit FWs in FI trees were greater than those of DI or SI trees at 8 weeks AFB. At harvest, FI trees bore the largest fruits, and SI trees the smallest fruits. The FWs of individual fruits at harvest in the FI and DI treatments decreased as crop load increased, but no such relationship was apparent for SI trees. The oil content of the mesocarp increased as PLWP increased from approx. –3.5 MPa to –1.5 MPa. The oil content of FI trees at harvest decreased from 53.1% to 45.7% dry weight as fresh fruit yield increased from 5 – 25 kg dm–2 trunk cross-sectional area. However, crop load did not have any effect on the oil content of the mesocarp in DI trees. Fruit maturation was delayed by irrigation. Maturation index also decreased (indicating delayed maturation) as the crop load on FI or DI trees increased, but did not vary with crop level in SI trees.This work was supported by the Centro Sperimentale per la Ortofrutticoltura per la Maremma Toscana, Spanish Ministry of Education Project REN 2001-1502 and Integrated Action Italy-Spain 2001-0222. We thank Francesco Tomei, Matteo Serravalle and Ester GarciaCuevas for technical assistance,Antonio de Haro for use of the nuclear magnetic resonance analyser, and Agenzia Regionale per lo Sviluppo e l’Innovazione nel Settore Agricolo-forestale (A.R.S.I.A.) for providing meteorological records

Irrigation differently affects endocarp and mesocarp growth during olive fruit development

To determine the growth response of the olive fruit mesocarp and endocarp to tree water status we subjected field-grown trees (Olea europaea L. 'Leccino') to different irrigation regimes. Tree water status was assessed as pre-dawn leaf waterpotential (Ψw), fruit tissue growth as fresh weight (FW) and dry weight (DW). Fruit weight responded readily to Ψw and reflected differences in tree water status. Mesocarp FW was positively correlated to Ψw and the response was evident starting at 15 weeks after full bloom (AFB) through harvest. The endocarp FW responded weakly to severe water deficit and by 15 weeks AFB had grown to full size. The pulp/pit ratio, expressed on FW basis, tended to decrease as the level of water deficit increased with Ψw below -2 MPa. The mesocarp DW was unaffected by tree water status at 9 weeks AFB and only slightly decreased when Ψw was less than -2 MPa at 20 weeks AFB. The results indicate how the behavior of different tissues and growth processes during fruit development affect the overall fruit response to water status

Olive fruit growth and productivity under different irrigation regimes and crop loads

A field study was conducted on young olive trees (Olea europaea L. 'Leccino') in Tuscany (Italy) to assess the combined effect of crop load and different irrigation regimes on fruit growth parameters and productivity. To establish heavy or low crop loads trees were hand-thinned between 5 and 6 weeks after full bloom (AFB). Drip irrigation was used to impose three irrigation regimes whereby pre-dawn leaf water potential (PLWP) was maintained: a) greater than -1.1 MPa (FI, fully-irrigated); b) between -1 and -3.3 MPa (DI, deficit irrigated); c) between -2.1 and -4.5 MPa (SI, stress irrigated). The effect of crop load on fruit tissue growth depended on the irrigation regime. Fruit mesocarp fresh weight was affected by both irrigation level and crop load, whereas endocarp fresh weight was affected only by the irrigation regime. Within each irrigation treatment, the mesocarp fresh weight was higher at low than at high crop load. However, as for dry weight, the mesocarp of SI or DI trees was smaller than that of FI trees only in high cropping trees, but not for low cropping trees. High crop loads significantly decreased fruit oil content (% dw) of FI trees. Comparing trees with high crop loads, DI showed higher fruit oil content than FI. Fresh fruit yield of SI and DI trees was 36 and 76% that of FI trees, respectively. FI and DI trees had similar fruit number; fruit number for the SI trees was 66% that of FI treatment. Oil yield per tree was similar for the FI and DI treatments, but less for the SI trees, which produced only 51% of the oil of FI trees (68% if expressed on a trunk cross sectional basis).Peer Reviewe

Acclimation ex vitro: How to improve the root system

Acclimation ex vitro is considered one of the most critical stages of the whole micro-propagation cycle. The root system is still weak and root growth and absorption need to be improved to compensate the increasing leaf transpiration and need of nutrients. The experiments presented in this study aimed to improve the aerial and root growth by using different substrates (type and mode of filling of the pots) in combination with specific fertilizers and replacing part of the root absorption with nutrient application to the leaves. The supply of mineral elements and organic compounds to the leaves in synergy with the available reserves in the seedlings can avoid the increasing of the cost of the absorption process for the plantlet. Results confirm the importance of the substrate to affect root growth and establishment. The quality of the growth of root and foliar P, K, Ca, Mg, and humic acids application positively influenced the growth and the plant settlement. Results showed that foliar applications in fertilized growing media are able to enhance vegetative growth, dry matter accumulation and basal steam diameter in all the tested clones. When nonfertilized growing media are used, foliar application is less effective in controlling vegetative growth to obtain the required height and basal stem diameter. This study suggests that is advisable to have a micro-porous substrate and apply moderate fertilizations through the substrate. The supply of the nutrients to the leaves resulted in bigger, but well hardened plants. It is possible to argue that changing concentrations and ratio among the different elements according to the acclimation cycle stage would balance vegetative growth and reduce hidden stresses