scholarly journals Potential pollen vectors of the mass flowering tree Acacia dealbata, within its natural range in southern Tasmania

2020 ◽  
Vol 154 ◽  
pp. 9-26
Author(s):  
AR Griffin ◽  
AB Hingston ◽  
CE Harwood ◽  
JL Harbard ◽  
MJ Brown ◽  
...  
2021 ◽  
Author(s):  
Stephen J Trueman ◽  
Wiebke Kämper ◽  
Joel Nichols ◽  
Steven M Ogbourne ◽  
David Hawkes ◽  
...  

Abstract Background and Aims Pollen limitation is most prevalent among bee-pollinated plants, self-incompatible plants, and tropical plants. However, we have very little understanding of the extent to which pollen limitation affects fruit set in mass-flowering trees despite tree crops accounting for at least 600 million tons of the 9,200 million tons of annual global food production. Methods We determined the extent of pollen limitation in a bee-pollinated, partially self-incompatible, subtropical tree by hand cross-pollinating the majority of flowers on mass-flowering macadamia (Macadamia integrifolia) trees that produce about 200,000–400,000 flowers. We measured tree yield and kernel quality and estimated final fruit set. We genotyped individual kernels by MassARRAY to determine levels of outcrossing in orchards and assess paternity effects on nut quality. Key Results Macadamia trees were pollen limited. Supplementary cross-pollination increased nut-in-shell yield, kernel yield and fruit set by as much as 97%, 109% and 92%, respectively. The extent of pollen limitation depended upon the proximity of experimental trees to trees of another cultivar because macadamia trees were highly outcrossing. Between 84% and 100% of fruit arose from cross-pollination, even at 200 m (25 rows) from orchard blocks of another cultivar. Large variations in nut-in-shell mass, kernel mass, kernel recovery and kernel oil concentration were related to differences in fruit paternity, including between self-pollinated and cross-pollinated fruit, thus demonstrating pollen-parent effects on fruit quality, i.e. xenia. Conclusions This study is the first to demonstrate pollen limitation in a mass-flowering tree. Improved pollination led to increased kernel yield of 0.31–0.59 tons per hectare, which equates currently to higher farm-gate income of approximately US3,720–US7,080 per hectare. The heavy reliance of macadamia flowers on cross-pollination and the strong xenia effects on kernel mass demonstrate the high value that pollination services can provide to food production.


1982 ◽  
Vol 12 (4) ◽  
pp. 814-821 ◽  
Author(s):  
A. M. Townsend ◽  
J. W. Wright ◽  
W. F. Beineke ◽  
R. P. Guries ◽  
C. A. Mohn

Red maple (Acerrubrum L.) seedlings grown from seed collected from throughout the species' natural range were planted in five states: Ohio, Michigan, Indiana, Wisconsin, and Minnesota. Flowering was almost exclusively dioecious and commenced in certain precocious progenies in the Ohio plantation 3 years after seed germination. Significant differences were found in all plantations among 7- and 8-year-old progenies in percentage of trees with flowers. Three plantations had differences in the number of flower buds per flowering tree and percentage of trees with winter injury. Variation among seedlots was apparent for length of the terminal leader injured by cold at two sites and for earliness of flushing in all plantations where recorded. Frequency of winter injury and time of budbreak of progenies showed a close relationship to geographic and climatic variables of seed sources, with northernmost progenies being less frequently injured and beginning growth first. There was also consistent progeny response between plantations in these two traits. Progeny from high elevations in the central and southern regions had less winter injury than progeny from low elevations. Flushing occurred in the seed lot sequence of northernmost origin first, southern next, and midlatitude last. Correlations of flowering frequency of progenies common to several plantations were in many cases significant, but correlations between plantations for numbers of flowers (per flowering tree) were less often significant.


2013 ◽  
Vol 20 (3) ◽  
pp. 376-385
Author(s):  
Gao Jiangyun ◽  
Sheng Chunling ◽  
Yang Shuxia

2021 ◽  
Author(s):  
Nicole Beyer ◽  
Felix Kirsch ◽  
Doreen Gabriel ◽  
Catrin Westphal

Abstract Context Pollinator declines and functional homogenization of farmland insect communities have been reported. Mass-flowering crops (MFC) can support pollinators by providing floral resources. Knowledge about how MFC with dissimilar flower morphology affect functional groups and functional trait compositions of wild bee communities is scarce. Objective We investigated how two morphologically different MFC, land cover and local flower cover of semi-natural habitats (SNH) and landscape diversity affect wild bees and their functional traits (body size, tongue length, sociality, foraging preferences). Methods We conducted landscape-level wild bee surveys in SNH of 30 paired study landscapes covering an oilseed rape (OSR) (Brassica napus L.) gradient. In 15 study landscapes faba beans (Vicia faba L.) were grown, paired with respective control landscapes without grain legumes. Results Faba bean cultivation promoted bumblebees (Bombus spp. Latreille), whereas non-Bombus densities were only driven by the local flower cover of SNH. High landscape diversity enhanced wild bee species richness. Faba bean cultivation enhanced the proportions of social wild bees, bees foraging on Fabaceae and slightly of long-tongued bumblebees. Solitary bee proportions increased with high covers of OSR. High local SNH flower covers mitigated changes of mean bee sizes caused by faba bean cultivation. Conclusions Our results show that MFC support specific functional bee groups adapted to their flower morphology and can alter pollinators` functional trait composition. We conclude that management practices need to target the cultivation of functionally diverse crops, combined with high local flower covers of diverse SNH to create heterogeneous landscapes, which sustain diverse pollinator communities.


Mycorrhiza ◽  
2021 ◽  
Vol 31 (3) ◽  
pp. 383-388 ◽  
Author(s):  
Cyrille Bach ◽  
Pauline Beacco ◽  
Pierre Cammaletti ◽  
Zhixiao Babel-Chen ◽  
Emilie Levesque ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Károly Lajos ◽  
Ferenc Samu ◽  
Áron Domonkos Bihaly ◽  
Dávid Fülöp ◽  
Miklós Sárospataki

AbstractMass-flowering crop monocultures, like sunflower, cannot harbour a permanent pollinator community. Their pollination is best secured if both managed honey bees and wild pollinators are present in the agricultural landscape. Semi-natural habitats are known to be the main foraging and nesting areas of wild pollinators, thus benefiting their populations, whereas crops flowering simultaneously may competitively dilute pollinator densities. In our study we asked how landscape structure affects major pollinator groups’ visiting frequency on 36 focal sunflower fields, hypothesising that herbaceous semi-natural (hSNH) and sunflower patches in the landscape neighbourhood will have a scale-dependent effect. We found that an increasing area and/or dispersion of hSNH areas enhanced the visitation of all pollinator groups. These positive effects were scale-dependent and corresponded well with the foraging ranges of the observed bee pollinators. In contrast, an increasing edge density of neighbouring sunflower fields resulted in considerably lower visiting frequencies of wild bees. Our results clearly indicate that the pollination of sunflower is dependent on the composition and configuration of the agricultural landscape. We conclude that an optimization of the pollination can be achieved if sufficient amount of hSNH areas with good dispersion are provided and mass flowering crops do not over-dominate the agricultural landscape.


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