Studies in the Metabolism of Crassulacean Plants: The Diurnal Variation in Organic Acid and Starch Content of Bryophyllum calycinum

Pucher, George W.; Leavenworth, Charles S.; Ginter, Wanda D.; Vickery, Hubert Bradford

doi:10.1104/pp.22.4.360

Cited by 34 publications

(21 citation statements)

References 4 publications

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“…In relation to the long established fact that a light period must precede a dark period for photoperiodic effectiveness (9), it is suggestive to note that sugars have been indicated as prerequisites for organic acid formation at night (23,24,29) and sugars are clearly not formed during the darkness. With respect to the products of dark fixation, it is interesting that malic acid-the major product of dark fixation in a wide variety of plant tissues (27)-is not detectable after 8 hrs in vegetative short-day plants, but is abundantly present in photoinduced plants (table I).…”

Section: Discussionmentioning

confidence: 99%

“…The photoperiodic circumstances of the plants used were not controlled, so the products obtained at the end of the dark periods do not assist in the understanding of the mechanism of photoperiodic induction. In only a few studies (23,24) has attention been paid to the synthesis and utilization of individual compounds during extended night periods; in most instances in which they have been studied duration of the experiment was only a few minutes (3,25) or a few hours (34).…”

Section: Discussionmentioning

confidence: 99%

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Influence of Light and Darkness upon Carbon Dioxide Fixation.

Sen

Leopold

1956

Plant Physiol.

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For plants sensitive to photoperiodism light is generally essential for flowering, and the requirement for CO2 with the light indicates a photosynthetic function for the light period (21, 10). There appears to be an additional role of light in which it apparently alters a photoreceptor pigment controlling floral initiation (22).Evidence has been advanced recently that CO2 is also essential during the dark period for floral initiation in some short day plants (13) conditions. It has long been accepted that some materials synthesized in a high intensity light process are utilized in the long dark period essential for flowering of short day plants (9). This suggests that .a ttlIy of C*02 fixation in light and darkness during the period of photoperiodic induction with the aid of chromatographic and autoradiographic techniques may yield useful information regarding the biochemistrv of the photoperiodic reactions. MATERIALS AND METHODS Two short day species-Biloxi Soybean (Glycine Max L.) and Cocklebur (Xanthium pensylvanicum Wallr.), and one long day species-Wintex barley (Hordeum vulgare L.), were used. These were grown on gravel beds with nutrient solutions. Induction treatment was begun when the plants were at least 3 weeks o0l(. Short and long day species were maintaine(l in the vegetative condition by subjecting them to 16-and is leaves) when only the roots were removed. The leaves of soybean and cocklebur were selected to have a midrib length of 6 to 8 cm; for cocklebur such young leaves have been shown to have the maximum sensitivity (11). The leaves were cut under water and the petioles were then dipped in a complete nutrient solution. The method of application of CO2 was as described previously (13). The concentration of CO2 in the experimental atmospheres was 0.25 %, and the radioactivity was approximately 25 Mc/l of air. Where comparisons of 3 species are made in the tables, all 3 were exposed to the C*0, simultaneously in the same chamber.In the experiments on photosynthesis, the photosynthetic chamber was immersed in a glass water bath to minimize temperature changes inside the chamber. The chamber was evacuated briefly with an air circulating pump before C*02, was introduced. The C*02 was generated previously in a closed weighing bottle fitted with stop-cocks and forming a part of the assembly, and was swept into the experimental chamber with natural air when the stopcocks were opened. The light on the leaf surfaces was ca 3000 fc in intensity and was supplied by a 150 w reflector flood lamp for 15 minutes in all experiments.The plant material was weighed before introduction into the chamber, and immediately after cessation of the experiment was dropped into boiling 80 % ethanol and extracted on a water bath for 20 minutes. The alcoholic extract was decanted, and the tissues further crushed and extracted with fresh 80 % ethanol on a Waring Blendor for 5 minutes and the extract filtered. The combined filtrates and washings were concentrated under vacuum to a small volume, and then diluted with water t...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Influence of Light and Darkness upon Carbon Dioxide Fixation.

Sen

Leopold

1956

Plant Physiol.

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“…Where such fixation is observed, we assumed it to be directly related to CAM as determined in previous studies (3,5,13,15,17 (14). A physiological feature associated with many succulents is the night opening of stomates and their closure during the daytime (8,9), which is related to night accumulation of organic acids and their disappearance during the day-referred to as Crassulacean acid metabolism (2,10). This phenomenon is attributed by some to have an adaptive significance for conservation of water and CO2 in succulents (6,16 Figure 1.…”

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confidence: 99%

Water Conservation in Kalanchoe blossfeldiana in Relation to Carbon Dioxide Dark Fixation

Zabka¹,

Chaturvedi²

1975

Plant Physiol.

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The succulent Kalanchoe (4,17,18). During preliminary studies on CO2 dark fixation, we observed that plants treated on short photoperiods in complete nutrient solution also required less frequent replenishment of solution than plants treated on long photoperiods. This suggested to us a conservation of water uptake by short day plants even with an abundant and continuous source of water available.The object of this study was to treat Tom Thumb plants in nutrient solution with contrasting photoperiods and correlate the phenomenon of CO2 dark fixation with the tendency for water conservation. Where such fixation is observed, we assumed it to be directly related to CAM as determined in previous studies (3,5,13,15,17).

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“…CAM plant leaves (3,6,18,19). A renewal of interest in CAM plant metabolism has occurred recently due to the discovery of the C, cycle of photosynthetic carbon metabolism in sugarcane and other plants (11,14).…”

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confidence: 99%

Isolation of Mesophyll Cells from Sedum telephium Leaves

1973

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A technique is described for mechanically isolating metabolically active individual spongy mesophyll cells from the Crassulacean acid metabolism plant, Sedum telephium. Mature leaves are selected at about 2 PM when acidity is low, and three different media are used to reduce the problem of leaf acidity and to maintain isotonic conditions. The upper and lower epidermis is peeled from chilled leaves and the leaves are suspended in a buffered "soaking medium," then gently ground with a mortar and pestle. Cells and debris are separated using a "washing medium," with cells being filtered through a 136 micron net and collected on an 80 micron net. Cells then are suspended in a "cell suspension medium" and concentrated by centrifugation. Approximately 2 hours are required for the isolation procedure, and activity in C02 fixation is constant for up to 4 hours after isolation. Microscopic examination shows about 65% of the isolated cells appear intact and unplasmolyzed and are similar to leaf msophyll cells. Crassulacean acid metabolism plants generally are characterized by the accumulation of titratable acidity at night, followed by a loss of acidity during the day in their leaves, while the leaf stomata open principally at night, and starch accumulation and degradation occur principally in the day and night, respectively (2,5,16 rooted then transplanted in a medium of soil, sand, and vermiculite (1 :1:1 v/v/v) in a house with a light intensity between 4000 and 6000 ft-c. Day temperatures ranged from 21 to 25 C, and night temperatures ranged from 17 to 20 C. The plants were watered two times per week in the morning.CO2 Incorporation with Isolated Cells. In addition to substrates, cells, and cofactors. as specified in each experimental setup, the total mixture of 250 ,ul contained: 50 mm Trizma base adjusted with MES to pH 8.0, 2 mm EDTA, 1 mM MnCl2, 2 mm NaNO.,, 5 mm MgCl2. 5 mM K2HPO4, and 350 mM sorbitol. The vial was placed in a 30 C temperature-controlled water bath. Light intensity was 2500 ft-c at the reaction mixture surface. Two minutes were allowed for temperature adjustment, and then "4C-labeled NaH CO. was pipetted into the mixture at a final concentration of 5 mm to start the reaction. Each vial was shaken a few times during the course of the experiments to prevent cell precipitation. Samples of 50 p.1 were taken at specific times and put in a vial containing 50 ,ul of 20% (w/v) trichloroacetic acid. Scintillation liquid (11 ml) was added. and unincorporated "CO2 removed by N. flushing for I min before the samples were counted for appropriate times. Liquid scintillation solutions were prepared by adding 4 g of BBOT (2,5-tert-butyl-benzoxyzalythiophene) to 1 liter of 700 ml of toluene plus 300 ml of ethanol solution and kept at 10 C in the dark (8. 17). RESULTSA number of CAM plant leaves were surveyed to see if intact photosynthetic cells could be released by mechanical means using a mortar and pestle. The plants examined included: 97

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Studies in the Metabolism of Crassulacean Plants: The Diurnal Variation in Organic Acid and Starch Content of Bryophyllum calycinum

Cited by 34 publications

References 4 publications

Influence of Light and Darkness upon Carbon Dioxide Fixation.

Influence of Light and Darkness upon Carbon Dioxide Fixation.

Water Conservation in Kalanchoe blossfeldiana in Relation to Carbon Dioxide Dark Fixation

Isolation of Mesophyll Cells from Sedum telephium Leaves

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