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

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

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

Pruning management in a high-density olive orchard

The effect of different pruning strategies and times on olive vegetative-reproductive behavior was studied in a 5-year-old high-density orchard (1250 trees ha-1, cultivar ‘Ascolana tenera’). Compared treatments were a) winter hedging and topping, b) summer hedging and winter topping, c) winter hedging and summer topping, and d) summer hedging and topping. Selective spring pruning to a conical shape of the canopy was used as a control. Results showed no significant differences between the tested treatments regarding the maximum canopy diameter (along and perpendicularly to the row). Topping significantly constricted the tree height recorded at the end of the season when compared with the control (3.5±0.46 m); in particular, summer application maintained the final tree height at 2.5±0.21 m. Summer topping and hedging significantly reduced the canopy volume compared with winter and selective spring (control) pruning. No significant differences between the treatments were recorded regarding the number of newly emitted sprouts on the central leader and primary branches, whereas the length of these sprouts was significantly shorter for the trees with summer topping. Vegetative re-sprouting was mainly recorded in the upper portion of the canopy (above 2.0 m), and the total length of the new sprouts in this portion was significantly different for summer and winter pruning (1.2±0.08 and 18.7±0.92 m, respectively). No significant differences between the treatments were registered for the seasonal vegetative growth of 1-year-old mixed shoots. Fruit yield per tree was significantly higher following the winter hedging and summer topping treatment compared with summer hedging and topping (47% increase) and selective spring pruning (control, 64% increase). Results suggest that correct pruning management (winter hedging and summer topping) contributes to maintaining a good vegetative-reproductive balance of young trees (reduced vegetative re-sprouting and high fruit production) in high-density olive orchards

Inflorescence characteristics and pollination compatibility of two local olive cultivars in high-density plantation

The self-fertilization and the cross-fertilization rate represent important factors in determining the suitability of local olive varieties to the high-density plantation. The inflorescence and flowering features, and the fruit set were investigated in 2016 (OFF year) for ‘Piantone di Mogliano’ (PM) and ‘Piantone di Falerone’ (PF), two promising local cultivars, in a young high-density olive orchard (1,250 trees ha-1) located in Maiolati Spontini (central Italy) with controlled pollination. Piantone di Falerone showed a higher percentage of open flowers compared to Piantone di Mogliano at the same date (June 3). The fruit set was determined under self-, cross- (PM×PF and PF×PM) and free-pollination conditions on small fruiting branches. The self- and cross-fertilization rate was tested closing the branches in paper bags before flowering onset. ‘Piantone di Falerone’ showed a higher number of inflorescences (positively correlated with the number of ramifications per fruiting branch) and a lower number of flowers per inflorescence compared to ‘Piantone di Mogliano’ so that finally no significant differences were recorded on the total number of flowers per fruiting branch in the two tested cultivars. ‘Piantone di Mogliano’ showed a lower number of perfect flowers due to a higher percentage of male flowers (ovary abortion) compared to ‘Piantone di Falerone’. According to fruit set, ‘Piantone di Falerone’ resulted self-sterile (no fruit set in paper bags with self-pollination) and ‘Piantone di Mogliano’ partially self-compatible. No differences on fruit set were recorded between the cultivars in free-pollination conditions (p=0.26), whereas in cross-pollination condition, inside paper bags, the combination PM×PF resulted in a higher (p=0.004) fruit set compared to the PF×PM one. Present results provide helpful information on the characteristics of the inflorescence, flowering time and self and non-self-fertility of ‘Piantone di Mogliano’ and ‘Piantone di Falerone’ and suggest the use of other cultivars as pollinators to increase fruit set in free pollination conditions