Extensor and Flexor Protoplasts from <i>Samanea</i> Pulvini

Gorton, Holly L.; Satter, Ruth L.

doi:10.1104/pp.76.3.680

Cited by 26 publications

(23 citation statements)

References 16 publications

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“…Calibration with NaCl standard solutions was repeated after each pair (fresh and frozen-thawed) of leaf measurements. When the pressure chamber was used, pinnae were harvested into plastic bags and kept on ice for up to 10 In closed pulvini (Fig. 3c), the appearance of high osmotic concentrations in flexor cells during the night coincided with the development of the capacity to close fully.…”

Section: Abstracimentioning

confidence: 99%

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Water Relations in Pulvini from Samanea saman

Gorton

1987

Plant Physiol.

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Biological Sciences Group U-42, University ofConnecticut, Storrs, Connecticut 06268 ABSTRACI The movement of Samwaea leaflets depends upon changes in the curvature of the pulvinus at the base of each leaflet. Pulvinar bending and straightening, in turn, are driven by the movement of water between opposing (extensor and flexor) sides of the pulvinus. Although water movement depends on water potential (1) and thus on osmotic potential (X) and hydrostatic pressure (P), none of these parameters have been measured in Samauea. In this investigation, il and X were measured and P was calculated for extensor Leaves and leaflets of the nyctinastic, leguminous tree Samanea saman (Jacq.) Merrill3 are usually spread horizontally during the day and folded tightly into a vertical orientation at night (2,20). These movements are brought about by the bending and straightening ofcylindrical motor organs, or pulvini, that subtend the leaf, the pinnae and the pinnules (see Fig. 2 (12,13,19). However, the magnitude and direction of the H+ fluxes varies with the 74 of the medium (16). These results are suggestive of a turgor-sensing mechanism, but they are difficult to interpret because we know very little about the I on the extensor and flexor sides of the pulvinus. If these in vitro experiments are to have maximum relevance to events occurring in whole pulvini, we must be able to design an appropriate bathing medium, with 7r balanced against the tissue , and we must understand the effects of excision.Pulvinar bending depends upon water movement, and thus on the I, wr, and P on the two sides of the pulvinus. regime at 27°C, as described in Gorton and Satter (10). Terminal secondary pulvini were used for all experiments. A protractor was used to measure leaflet angles (the angle between the rachis and the rachilla).Osmolality Measurements. Fluid from extensor and flexor tissues was obtained by two methods.1. Strips ofextensor and flexor tissue were excised as described in Iglesias and Satter (12). The tissue strips were squashed between a glass slide and a stainless steel spatula, and expressed fluid was collected with a glass microcapillary, all within a 4Abbreviations: ir = osmotic potential; PEG = polyethylene glycol (mol wt 3350); P = hydrostatic pressure; 1 = water potential (+ = r + P). 945www.plantphysiol.org on May 11, 2018 -Published by Downloaded from

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Section: Abstracimentioning

confidence: 99%

“…Samanea saman (Jacq.) Merrill trees were grown in 26 cm diameter clay pots on a 16 h light:8 h dark regime at 27°C, as described in Gorton and Satter (10). Terminal secondary pulvini were used for all experiments.…”

Section: Abstracimentioning

confidence: 99%

Water Relations in Pulvini from Samanea saman

Gorton

1987

Plant Physiol.

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“…The difference between extensor and flexor protoplasts is closer to what one might expect for a partially closed pulvinus (11,12). We have reported other indications that these pulvinar protoplasts might be taking on some of the characteristics of cells in a closed pulvinus and discussed why these changes might be expected (2).…”

Section: Discussionmentioning

confidence: 66%

“…Protoplasts were isolated from extensor and flexor cortical cells from open pulvini ofSamanea saman, as described in (2). Although sorbitol was the major external osmoticum throughout protoplast isolation, it is not stable in the electron beam, and thus it had to be replaced before mounting the protoplasts for x-ray analysis.…”

Section: Methodsmentioning

confidence: 99%

Extensor and Flexor Protoplasts from Samanea Pulvini

Gorton¹,

Satter²

1984

Plant Physiol.

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Concentrations of K, Cl, P, S, and Ca in extensor and flexor protoplasts from open pulvini of the nyctinastic tree Samanea saman were estimated using x-ray microanalysis. This technique is particularly suitable when absolute bumbers of protoplasts are low, because less than 100 protoplasts are required to obtain statistically significant data. Flexor protoplasts contain similar concentrations of P and S but almost twice as much K and Cl as extensor protoplasts. Low (2). Although sorbitol was the major external osmoticum throughout protoplast isolation, it is not stable in the electron beam, and thus it had to be replaced before mounting the protoplasts for x-ray analysis. We used a final wash of 60 mm sucrose with 280 mm NaCl, RbCl, NaBr, or RbBr to replace the sorbitol (normally 500 mM) while maintaining approximately the same osmotic concentration.' Supported by grants from the National Science Foundation to R. L. S.2 Samanea saman has been reassigned to the genus Pithecolobium. We retain the name Samanea for continuity with earlier literature.3 Because x-ray analysis detects total elemental content without regard to ionic form, Na, Cl, K, Mg, P, S, Rb, and Br are used to designate these elements, even though they are generally present in ionized form.This step was performed at 0°C to minimize uptake of ions from the wash solution. Washes with LiNO3 or organic anions were considered because their low atomic weight components would interfere less with x-ray analysis, but they were not used because they disturbed leaflet movement in the closely related plant, Albizziajulibrissin (unpublished data; also, Satter et al. [8]).Immediately after the final wash in one of these solutions, protoplasts were mounted on sample supports made from the bottoms of aluminum weighing boats (Fisher Scientific). Aluminum was used because it has a low atomic number, high heat conductivity, and is easier to handle than thin pieces of plastic, or plastic films. The inside surface of the bottom of a weighing boat was coated with 0.5 ml 0.2% formvar (w/v) in dichloroethane and drained. The bottom of the weighing boat (0.09-0.1 mm thick) was then cut into squares about 2 mm on a side. A 2 Al droplet of 0.2% (w/v) polylysine in 80% (v/v) ethanol was layered over the formvar on each square and allowed to dry. One droplet of protoplast suspension (3-4 ,ul) was placed on each square. Protoplasts were allowed to settle, and the droplet was drained offwith Whatman No. 3 filter paper, leaving protoplasts adhering to the polylysine. Each square of foil with its adhering protoplasts was immediately frozen in liquid freon 22 (cooled to -145 to -150°C with liquid nitrogen) and lyophilized. Ten to 15 replicate samples were prepared in this way from each population of extensor and flexor protoplasts. Ten to 15 min elapsed between the time the cold, final wash was started and the time the last sample was frozen. The lyophilized samples were stored over P205 under light vacuum.As many as 10 aluminum squares, each bearing a population of lyop...

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“…By Figure 5. S. saman pulvinar protoplasts (from both the extensor and flexor regions) also were bound by the F8IVE9 antibody, demonstrating that target antigen was present on the plasma membranes of cells from a species other than A. sativa (Samanea protoplasts were generously provided by Hak Yong Kim and were prepared according to a modification ofthe method ofGorton and Satter [7]). …”

Section: Temporal and Tissue Control Of Antigenic Expressionmentioning

confidence: 99%