Plant‐pollinator interactions are highly important because of its direct link to plant fitness and because such interactions involve species at different trophic levels. Our understanding of ...competitive and facilitative interactions among plants for pollination is of large importance to govern conservation of species and management of crop production. Still we know little about the scale dependency of plant–plant interactions for pollinator visitation which is central to both basic and applied ecology. Here, I tested whether plant–plant interactions for bumblebee visitation and subsequent reproduction were scale‐dependent by studying the ecologically and economically important red clover (Trifolium pratense) and its floral neighbourhood. I expected that high floral densities at small scale could trigger facilitative interactions due to concentration effects of pollinators. This was expected to change into competitive interactions when floral densities became higher at coarser scales because of dilution effects. I also expected that increased bumblebee visitation would increase fruit production in red clover. The interaction for pollination success in red clover appeared to be scale‐dependent in the landscape under study. At plot scale, the bumblebee visitation rate to red clover inflorescences increased with both intra‐ and interspecific floral density, indicating facilitative interaction for pollinator visitation among red clover flowers and its nearest floral neighbourhood. Increased visitation of bumblebees led to subsequent increased fruit set, but there was a saturating effect as fruit set did not increase when visitation rates exceeded a certain level. As the floral neighbourhood became denser at a coarser scale, the interactions for pollinator visitation changed towards competition. This study shows that key ecological processes such as plant–pollinator interactions may indeed be scale‐dependent and that the relative importance of competition and facilitation among plants for attracting pollinators may change with scale. The density of the floral neighbourhood of a focal species (e.g. key‐, rare‐, crop species) may thus be of large importance for its pollination and fruit production. My findings suggest that increasing floral densities at fine scales may have facilitative effects on pollinator visitation to red clover, whereas pollinators may be drawn away when floral resources become denser at coarser scale.
► Drought treatment increased all points of the OJIP curves in FB200 plants. ► L and K-band increased after five days of water stress in FB200 with partial recovery after one week rewatering. ► With ...rewatering of plants, declines of Fv/Fm values persisted by at least three days in FB200 passion cultivar. ► The two passion cultivars differed in the plasticity of their response to drought and rewatering. ► Under drought conditions the FB300 plants possess an advantage over FB200 plants in terms of stability and efficiency in utilizing energy.
Chlorophyll a fluorescence of two passion fruit cultivars grown in a greenhouse were evaluated to determine the effect of induced water stress and recovery on young plants. One month-old passion (Passiflora edulis Sims) cv. Yellow Master (FB200) and Maguary (FB300) plants were evaluated in 11.0L pots after 11 days of water withholding, imposed by suspension of irrigation, and after six days of rewatering. Drought treatment increased all points of the OJIP curves in FB200 plants. With water stress, reductions of ΔVOP occurred in FB300 only in J–I phase, while all phases from OJIP curve were reduced in FB200. J–I phase showed signals of recovery within six days in FB200 but this period of rewatering was not sufficient for recovery of O–J and I–P phases. There was total recovery of ΔVOP values in FB300 followed by an increment of efficiency which an electron is transfer to photosystem I (PSI) acceptor side, evidenced by a positive increase of I–P phase after stress. To FB200, L and K-band increased after five days of water stress with partial recovery after one week rewatering. But, to FB300, significant difference of bands was only observed at 11 days from water withholding and the difference between water treatments was very evident, with total recovery after rewatering. On the day of maximum stress, the maximum efficiency of PSII (Fv/Fm ratio) decreased significantly in both passion cultivars while the effective antenna size of an active reaction center (ABS/RC) values increased 24 and 11% in FB200 and FB300, respectively. With rewatering of plants, declines of Fv/Fm values persisted by at least three days in FB200 passion cultivar. Also, increases of ABS/RC in FB200 (+110%) was irreversible and persisted until the six day after rewatering. These findings showed that two passion cultivars differed in the plasticity of their response to drought and rewatering and further shows that under drought conditions the FB300 plants possess an advantage over FB200 plants in terms of stability and efficiency in utilizing energy. Measurements of OJJIP fluorescence transients, Fv/Fm and ABS/RC ratios, analyzed using the JIP-test, were good tools for the screening of the potential to cope with and to recover from drought.
Cover crops significantly affect soil quality, and growth characteristics in apple orchards, but reports are scarce. Therefore, the present study was conducted on a 15-year-old apple orchard ...(cultivar ‘Red Gold’) at Kashmir valley (32°22′–34°43′N, 73°52′–75°42′E; 1850 m.a.s.l.) to determine the influence of grass (
Festuca arundinaceae
) and legume (
Trifolium pratense
) bi-culture (GLBC) on soil properties viz. soil organic carbon (SOC), labile carbon (LC), total nitrogen (TN), potassium (K), magnesium (Mg), nitrogen (N), phosphorus (P), copper (Cu), zinc (Zn), manganese (Mn), iron (Fe); and plant growth characteristics like trunk girth (TG), trunk cross-sectional area (TCSA), fruit yield (FY), and yield efficiency(YE), relative to a no cover crop control. GLBC produced 27.9 ± 3.9 and 7.5 ± 0.8 tons/ha green and dry herbage. Plant growth characteristics differed significantly (
p
< 0.05), with highest TG (38.89 ± 1.54 cm) and TCSA (123.07 ± 9.61 cm
2
) in GLBC and lowest (36.22 ± 0.97 and 107.11 ± 5.72, respectively) in control. The treatments differed for FY and YE, and maximum FY (30.63 ± 2.81 t/ha) and YE (0.25 ± 0.01 kg/cm
2
) was recorded in GLBC. Average SOC (12.53 g kg
−1
), LC (0.90 g kg
−1
), and TN (0.76 g kg
−1
) were 20.7, 27.7, and 13.3% greater in GLBC than control at 0–30 cm depth. Relative to control, SOC accumulation in GLBC was 14.15%, and soils sequestered 3.04 Mg C ha
−1
. For nutrients, differences between treatments were limited for Mg, moderate for P, and Cu; and strong for Mn and K. The findings convey that GLBC adds enough residues to soil to cause measurable changes in SOC and offers potential for C sequestration and soil sustainability.
•This paper first described lychee using extended BBCH-scale.•Seven and 41 secondary growth stages were described.•Our description combined words, photos and figures.
This study presents codes and ...detailed crop-specific descriptions for the growth stages of the lychee tree in southern China. Our codes are based on the extended Biologische Bundesantalt, Bundessortenamt, and Chemische Industrie (BBCH)-scale and describe the growth stages of the lychee plant using a three-digit numerical system. A total of 7 principal growth stages are described for bud, leaf, and shoot development, inflorescence emergence, flowering, fruit development, and fruit maturity. In addition, 41 secondary growth stages are described. The extended BBCH-scale for lychee presented in this study is broadly applicable because it describes all the phenophases pertaining to bud, shoot, leaf, panicle, and fruit development, as well as the growth pattern of the shoots and their seasonal variation. These data should facilitate more effective management of lychee orchards and contribute to the standardization of international testing systems for fruit growing.
Frente a las repetidas crisis vitivinícolas en Mendoza se diseñaron disímiles proyectos para diversificar la matriz agroindustrial. La fruticultura tuvo mayor éxito y logró posicionarse en el mercado ...nacional. Entre las múltiples estrategias que adoptó el Estado para la expansión de nuevos cultivos se destacó la organización de exposiciones locales, y su participación en encuentros similares a escala regional e internacional. En este artículo discutiremos sobre el efecto multiplicador de las mismas. Al mismo tiempo, se destaca la organización de conferencias nacionales, nos preguntamos si estos encuentros funcionaron también como un mecanismo para dar visibilidad a las principales problemáticas del sector.
Sown wildflower strips are increasingly being established in Europe for enhancing arthropod conservation and the provision of ecosystem services, including biotic pollination and natural pest ...control. Here we use floral traits to identify different plant functional effect groups. Floral resources were provided in four experimental levels characterised by a cumulatively increasing flower trait diversity and vegetation stand complexity. The first level consisted of a bare control strip, whilst in each subsequent level three wildflower species with different functional traits were added (Level 0: control; Level 1: three Apiaceae species; Level 2: three Apiaceae and three Fabaceae species; Level 3: three Apiaceae, three Fabaceae species, and Centaurea jacea (Asteraceae), Fagopyrum esculentum (Polygonaceae), Sinapis alba (Brassicaceae)). Plots with sown wildflower strip mixtures were located adjacent to experimental plots of organically-managed tomato crop, which is attacked by multiple pests and partially relies on bees for fruit production, and hence dependent on the provision of pollination and pest control services. Results obtained here show that the inclusion of functionally diverse wildflower species was associated with an augmented availability of floral resources across time, and this increased the abundance of bees and anthocorids throughout the crop season. Several natural enemy groups, such as parasitoids, coccinelids and ground-dwelling predators, were not significantly enhanced by the inclusion of additional flower traits within the strips but the presence of flower resources was important to enhance their conservation in an arable cropping system.
This paper presents and implements a framework for modeling the impact of land use practices and protection alternatives on nitrate pollution of groundwater in agricultural watersheds. The framework ...utilizes the national land cover database (NLCD) of the United State Geological Survey (USGS) grid and a geographic information system (GIS) to account for the spatial distribution of on-ground nitrogen sources and corresponding loadings. The framework employs a soil nitrogen dynamic model to estimate nitrate leaching to groundwater. These estimates were used in developing a groundwater nitrate fate and transport model. The framework considers both point and non-point sources of nitrogen across different land use classes. The methodology was applied for the Sumas–Blaine aquifer of Washington State, US, where heavy dairy industry and berry plantations are concentrated. Simulations were carried out using the developed framework to evaluate the overall impacts of current land use practices and the efficiency of proposed protection alternatives on nitrate pollution in the aquifer.
The vinegar fly Drosophila suzukii Matsumara (Diptera: Drosophilidae), native to Asia, recently invaded Europe and North America. By contrast to other frugivorous Drosophila species, D. suzukii lays ...eggs on ripening fruits, heavily reducing fruit production. Although cultivated host plants of D. suzukii are well documented, very little is known about wild hosts in the invaded areas. The American black cherry Prunus serotina Ehrh., a tree species native to North America, became one of the main woody forest invaders in Europe. One cause of its invasion success is the huge amount of fruit produced by P. serotina trees. A field survey showed that P. serotina is a suitable reservoir for the development and persistence of D. suzukii populations in European natural systems (on the forest area investigated, up to 70% of all the fruits of P. serotina were infested in one of the sampling sites). Laboratory tests demonstrated that D. suzukii prefers ripening cherries to ripe ones, therefore increasing the chance of the larvae to fully develop and reach maturity before the mesocarp of the fruit totally decays. Infestation of P. serotina cherries could reduce the life span of fruits, as well as their attractiveness to seed consumers and dispersers, yet P. serotina could represent a suitable plant reservoir promoting D. suzukii invasion in Europe and North America.
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