Nectar Production in Abutilon IV. Wate'r and Solute Relations

Findlay, Nele; Reed, ML; Mercer, FV

doi:10.1071/bi9710677

Cited by 17 publications

(1 citation statement)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is generally held that nectar sugar is transported mainly as sucrose in the phloem (Liittge & Schnepf 1976). Studies of nectar secretion often focus on processes at the sink, the nectary (Luttge 1977, Findlay et al 1971Reed et al 1971), but it can be equally fruitful to think in terms ofthe direction and rate of transport of assimilate in the phloem. The direction of phloem transport commonly depends on the rate of unloading at the sink (Gifford & Evans 1981;Cronshaw 1981).…”

Section: Nectar Secretion: Environmental Effectsmentioning

confidence: 98%

Honeybees and the nectar of Echium plantagineum L. in southeastern Australia

Corbet

Delfosse

1984

Australian Journal of Ecology

View full text Add to dashboard Cite

An account is given of the flower of Echium plantagineum in south-eastern Australia, including stages and timing of flowering, behaviour of raindrops in the flower and aspects of floral microclimate.The concentration of nectar solutes varied with time and site, with means varying from 2 to 62% (as g sucrose/100 g solution). There was a significant negative correlation between nectar solute concentration and ambient relative humidity: the drier the air, the more concentrated the nectar.Rates of nectar secretionperflower varied with the bagging method, with long-term bagging reducing net secretion rates, possibly because of reabsorption. Rates varied with time, day and site, with a temporal pattern of change suggesting a link between rates ofphotosynthesis and secretion. Maximum nectar secretion rates in short-term bagging experiments were ca. 300 fx.g sugar/flower/hr (equivalent to > 2 mglflower 124 hr).Secretion rate was correlated with flower density. As flower density increased, secretion rate per flower decreased; rate of sugar production per unit area increased relatively more slowly than flower density. E. plantagineum could produce > 500 mg sugarlm^lday.Honeybees foraged on E. plantagineum only at ambient air temperatures above ca. lTC unless irradiance exceeded ca. 750 W m~^. Foragers collected nectar or pollen alone, or both, with the type of visit significantly correlated with nectar solute concentration. Below 35% (as g sucrose/100 g solution) most bees took pollen only; above 40%, most took nectar.Mean standing crop of nectar was generally < 100 ixg/fiower when most bees were taking nectar, but could exceed WOO ixg/ftower when bees were absent or foraging mainly for pollen. Honeybees did not always remove all nectar from flowers they probed. Reabsorption of residual nectar may augment the following day's secretion.

show abstract

Section: Nectar Secretion: Environmental Effectsmentioning

confidence: 98%

Honeybees and the nectar of Echium plantagineum L. in southeastern Australia

Corbet

Delfosse

1984

Australian Journal of Ecology

View full text Add to dashboard Cite

show abstract

Ultrastructure of Nectaries in Relation to Nectar Secretion

Fahn

1979

American J of Botany

View full text Add to dashboard Cite

In the last 15–20 years, ultrastructural studies have added new important cytological information to the relatively rich literature on the morphology and light microscopy of nectaries. On the basis of these studies, the following main conclusions can be drawn regarding the relation between the ultrastructure of nectaries and the process of nectar secretion: (1) the transport of the pre‐nectar in the nectariferous tissue is mainly via the symplast; (2) the ER alone or the ER and the Golgi apparatus are involved in the process of secretion; (3) the elimination of nectar from the protoplast of the secretory cells is by reverse pinocytosis; (4) the outer walls of the secretory cells of nectaries in many plants possess wall ingrowths.

show abstract

Hydrodynamic radius alone governs the mobility of molecules through plasmodesmata

Terry

Robards

1987

Planta

228

147

View full text Add to dashboard Cite

Various fluorescent molecular probes have been injected into the cytoplasm of nectary trichome cells of Abutilon striatum to ascertain the conductivity of the plasmodesmata. Most of the probes were based on fluorescein conjugated to a range of amino acids and peptides. The probes are not broken down by cytoplasmic enzymes during the period of observation. The results indicate that there are no specific effects of aromatic amino acids, either polar or hydrophobic types, on the conductivity of the Abutilon plasmodesmata, contrary to reports for other plants. The conductivity of the plasmodesmata in the trichomes is slightly greater than for any that have been studied in the tissues of other plants. It is proposed that in Abutilon the mobility of a probe is determined solely by the effective Stokes radius of the molecule, and that the radius of the molecule is governed by the molecular weight and, in particular, by the nature of the side groups in the peptide chain attached to the fluorochrome. Calculations are presented which indicate that channels between material in the plasmodesmatal annulus are the most likely route for the diffusion of the probes, and that the width of individual channels in the annulus is close to 3 nm.

show abstract

Nectar Production in Abutilon IV. Wate'r and Solute Relations

Cited by 17 publications

References 16 publications

Honeybees and the nectar of Echium plantagineum L. in southeastern Australia

Honeybees and the nectar of Echium plantagineum L. in southeastern Australia

Ultrastructure of Nectaries in Relation to Nectar Secretion

Hydrodynamic radius alone governs the mobility of molecules through plasmodesmata

Contact Info

Product

Resources

About