Nectar production in the boreal forest lily Clintonia borealis

1981 ◽  
Vol 59 (2) ◽  
pp. 156-160 ◽  
Author(s):  
R. C. Plowright

Nectar secretion in unpollinated flowers of Clintonia borealis (Ait) Raf. (Liliaceae) began as the tepals first opened, reached a maximum at about the time the anthers dehisced, and ceased after the tepals began to curl back. Total lifetime sugar production was highly correlated with flower size and was not affected by daily nectar removals. Nectar concentration varied widely as a response to fluctuations in atmospheric relative humidity. It is suggested that since freshly secreted Clintonia nectar ranged in concentration from 4 to 63% sugar by weight, comparisons of nectar concentration among different species may not be meaningful unless accompanied by environmental data at and prior to the time of sampling.


Author(s):  
Pat Willmer

This chapter examines the biology of nectar, the main secondary floral reward in an evolutionary sense. As a commodity, nectar is easy for plants to produce and easy for animals to handle; its sugars are simple to metabolize and thus to use as a readily available fuel for an animal’s activities. Nectar is a crucial factor in determining the interactions of flowers and their visitors. The chapter first provides an overview of how floral nectar is produced in a nectary before discussing nectar secretion, the chemical composition of nectar, and nectar volume. It then considers nectar concentration and viscosity, nectar as a sugar and energy reward, and nectar as a water reward. It also explores daily, seasonal, and phylogenetic patterns of nectar production, how flowers control their nectar and their pollinators, and problems in measuring and quantifying nectar. The chapter concludes with an analysis of the costs of nectar gathering.



1993 ◽  
Vol 71 (10) ◽  
pp. 1394-1398 ◽  
Author(s):  
Leonardo Galetto ◽  
Luis Bernardello

Nectar secretion pattern and effects of nectar removal were compared in three Argentinean Solanaceae: Nicotiana glauca, which is hummingbird pollinated, and Nicotiana longiflora and Petunia axillaris, which are sphinx moth pollinated. Nectar volume, concentration, and sugar production were measured at different time intervals according to the species' flower life span. Nectar volume and total sugar production increased as a function of flower age in both species of Nicotiana analyzed; however, these parameters were quite stable in P. axillaris. This species produced less nectar and nectar sugar than the other two. When all sets with nectar removal were compared with the controls, significant differences were found in nectar volume and quantity of nectar sugar in N. longiflora, and in sugar concentration in P. axillaris. In the latter, the observed difference did not affect the total amount of sugar secreted. Nicotiana glauca did not show any significant difference in the parameters analyzed. Total nectar production was inhibited by periodic removal in N. longiflora, while in N. glauca and P. axillaris it was unaffected. Key words: nectar secretion pattern, nectar removal, Nicotiana, Petunia, Solanaceae.



2006 ◽  
Vol 16 (9) ◽  
pp. 882-887 ◽  
Author(s):  
Xiaodong Xie ◽  
Yibing Wang ◽  
Lisa Williamson ◽  
Geoff H. Holroyd ◽  
Cecilia Tagliavia ◽  
...  




2019 ◽  
Vol 105 (1) ◽  
pp. 115-125
Author(s):  
Miguel Ángel Molinero Polo ◽  
Vicente Soler Javaloyes

TT 209 was built in a wadi, a location that means it has been affected by flash floods since ancient times. The team in charge of its study and conservation has initiated a systematic programme of environmental data collection (temperature and relative humidity) in order to understand the natural conditions of the tomb and any transformations caused by archaeological work in its underground chambers, as well as to inform future conservation. These statistics can also be useful for excavation and conservation programmes in nearby tombs whose architectonic structure is similar and have also suffered from exposure to water damage.



2007 ◽  
Vol 37 (7) ◽  
pp. 1214-1226 ◽  
Author(s):  
L.A. Venier ◽  
J.L. Pearce

We examined a landbird community and its relationship to environmental variables within the boreal forest in north–central Ontario to evaluate its potential usefulness as an indicator of sustainable forest management. Our study had two components. First, we compared bird assemblages in mature forest stands inside Pukaskwa National Park (n = 17) with similar forested stands in a logged landscape (n = 18) over 3 years. We found significant separation of sites in the two treatments based on an ANOSIM (analogue of the standard univariate one-way ANOVA test) of the bird communities (R = 0.238, p < 0.001). We identified four significant indicators of the park landscape (bay-breasted warbler ( Dendroica castanea (Wilson, 1810)), black-throated green warbler ( Dendroica virens (J.F. Gmelin, 1789)), ovenbird ( Seiurus aurocapillus (L., 1766)), and red-eyed vireo ( Vireo olivaceus (L., 1766))) and five indicators of the logged landscape (black-backed woodpecker ( Picoides arcticus (Swainson, 1832)), brown creeper ( Certhia americana Bonaparte, 1838), winter wren ( Troglodytes troglodytes (L., 1758)), white-throated sparrow ( Zonotrichia albicollis (J.F. Gmelin, 1789)), and yellow-bellied sapsucker ( Sphyrapicus varius (L., 1776))). Some relationships were attributable to differences in vegetation, whereas other differences were attributable to the landscape context. Second, we used generalized additive models to examine the relationship of individual species with four sets of environmental data (understorey floristics, forest structure, overstorey composition, and landscape context) using the 35 sites noted above and 18 additional mature forest sites in the logged landscape (n = 53). We found that all four types of variables were frequently included in the best model based on Akaike's information criterion (AIC) (structure in 23 models, landscape in 20 models, overstorey in 19 models, and understorey in 15 models). We discuss our results in terms of their implications to forest management and note that our ability to map habitat for forest birds is substantially compromised by the lack of good spatial estimates of environmental variables that describe bird habitat.





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