Carbon Dioxide and pH Requirements of Non‐Photosynthetic Tissue Culture Cells

Nesius, Kneeland K.; Fletcher, John S.

doi:10.1111/j.1399-3054.1973.tb01186.x

Cited by 41 publications

(13 citation statements)

References 15 publications

(18 reference statements)

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“…Nash and Davies (20) did not observe these phases of growth in their work with suspension cultures of Paul's Scarlet rose. In the present study cells grown for 14 days in 80 ml of MPR medium had a 40-fold increase in fresh weight and a final yield of 19.7 g. Furthermore the growth kinetics showed distinct phases of growth comparable to those reported in previous work from this laboratory (6,9,21). The present work showed that when cells were grown in MPR medium without NH4+ only a 19-fold increase in fresh weight occurred, the fresh weight yield was reduced to 9.6 g, and the division and expansion phases were less distinct.…”

Section: Discussionsupporting

confidence: 76%

Ammonium Influence on the Growth and Nitrate Reductase Activity of Paul's Scarlet Rose Suspension Cultures

Mohanty¹,

Fletcher²

1976

Plant Physiol.

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Suspension cultures of Paul's Scarlet rose were grown in two defined media which differed only in their inorganic nitrogen content. Both possessed equal amounts of NO3' (24 mM), but differed in that NH4' (0.91 mM) was present in control medium; whereas, no NH4( was present in the test medium. A comparison of fresh weight increases over a 14-day growth period showed that NH4+ caused a 2-fold stimulation in growth and governed the pattern of development.Ammonium also caused a 2-fold increase in nitrate reductase activity but had little influence on the activity of representative enzymes from the Embden-Meyerhof pathway or citric acid cycle. Thus NH,4 enhanced the nitrate reductase activity which was correlated with increased growth.Ammonium had no influence on the in vitro activity of nitrate reductase which suggested that the stimulatory influence was due to an increased synthesis of the enzyme. The enhanced synthesis did not appear to be due to an increased availability of NO3+ since the uptake of NO3' by intact cells was not influenced by the presence of NH4+ during the period of most rapid increase in nitrate reductase activity.In previous work with suspension cultures of Paul's Scarlet rose, cells were shown to grow with only NO3+ serving as a nitrogen source, but maximum growth required a supplemental amount of either NH4+ or glutamine (22). Similar requirements were reported for suspension cultures of soybean (1, 23). Thus, in these tissue culture systems a reduced form of nitrogen such as NH4+ is required for the maximum utilization of NO3+ provided in the medium.It is well accepted that NO3+ induces the synthesis of NR1, the first enzyme in the pathway of NO3+ reduction. However, the regulatory role played by NH4+, end-product of NO3+ reduction, is less clearly understood. Ammonium has been shown to repress the induction of NR in Neurospora, Chlorella, and Lemnaceae (2). In most higher plants NH4+ either has no influence or it enhances the induction of NR by NO3-(2, 11).Based on extensive studies with genetic hybrids of corn and wheat, Hageman and colleagues (7,8)

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Section: Discussionsupporting

confidence: 76%

Ammonium Influence on the Growth and Nitrate Reductase Activity of Paul's Scarlet Rose Suspension Cultures

Mohanty¹,

Fletcher²

1976

Plant Physiol.

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“…Other investigators have looked at the long-term effect of pH on cultures and reported results apparently at odds with the acid-growth hypothesis. For zinnia mesophyll cultures (Roberts and Haigler, 1994), carrot embryo cultures (Smith and Krikorian, 1992), and rose cell-suspension cultures (Nesius and Fletcher, 1973), low-pH values promoted cell division, whereas cell expansion and elongation seemed to require a slightly higher pH. In zinnia mesophyll cultures the optimal pH for cell elongation was 5.5 to 6.0, whereas cell differentiation occurred when the pH of the medium decreased to 4.8.…”

Section: Discussionmentioning

confidence: 97%

“…Published evidence suggests that cell-suspension cultures do not show acid-growth responses (Nesius and Fletcher, 1973;Smith and Krikorian, 1992;Roberts and Haigler, 1994). In this investigation we examined the possibility that BY2 tobacco cell cultures possess an expansin-mediated growth mechanism.…”

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confidence: 99%

Acid-Growth Response and α-Expansins in Suspension Cultures of Bright Yellow 2 Tobacco

1998

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The possibility that Bright Yellow 2 (BY2) tobacco (Nicotiana tabacum L.) suspension-cultured cells possess an expansin-mediated acid-growth mechanism was examined by multiple approaches. BY2 cells grew three times faster upon treatment with fusicoccin, which induces an acidification of the cell wall. Exogenous expansins likewise stimulated BY2 cell growth 3-fold. Protein extracted from BY2 cell walls possessed the expansin-like ability to induce extension of isolated walls. In western-blot analysis of BY2 wall protein, one band of 29 kD was recognized by anti-expansin antibody. Six different classes of ␣-expansin mRNA were identified in a BY2 cDNA library. Northern-blot analysis indicated moderate to low abundance of multiple ␣-expansin mRNAs in BY2 cells. From these results we conclude that BY2 suspension-cultured cells have the necessary components for expansin-mediated cell wall enlargement.

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“…However, in some cell cultures the pH optimum for cell expansion has been shown to be higher than predicted by the acid growth hypothesis (Nesius and Fletcher, 1973;Smith and Krikorian, 1992). It has also been shown that long-term auxin-induced growth in coleoptiles has a pH optimum higher than predicted by the acid growth hypothesis .…”

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confidence: 88%

Cell Expansion and Tracheary Element Differentiation Are Regulated by Extracellular pH in Mesophyll Cultures of Zinnia elegans L

Roberts

Haigler

1994

Plant Physiol.

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as well as cell expansion in a variety of cell cultures (Minocha, 1987). For example, embryogenic carrot cultures can be maintained as preglobular stage proembryos at pH 4.0 but form mature embryos at pH 5.8 (Smith and m o n a n , 1990a, 1990b, 1992).tobacco thin-layer cultures, high p~ hcreased the ratio of flower bud to vegetative bud formation (Cousson et al., 1989(Cousson et al., , 1992Pasqua et al., 1991). Shoot gation was promoted at pH 4.8 in Euphorbia fulgens cultures (Zhang and Stoltzg 1989). In cultured CimS fmit vesiclesg TE differentiation had a pH o p h u m of 5.0 to 6.0 (Khan et al., 1986). With a few exceptions (Cousson et al., 1992;Smith and Krikorian, 1992), these studies were camed out in unbuffered medium. In one case (Pasqua et al., 1991), reported p~ changes of buffered cultures were nearly identical with those of unbuffered cultures.Few systematic studies have been camed out to characterthese effectst 'Onsidenng the potential influente Of extracellular pH On the growth and differentiation Of cultured Plant cells (for review, see Minochat 1987). In many of the studies in which pH-dependent effects on p w t h and development were noted, cultures were not buffered and pH was not monitored throughout the culture period (Banthorpe and Brown, 1990). It is difficult to draw conclusions from these studies, since it is clear that pH can fluctuate dramatically in unbuffered plant cell cultures. Suspension cultures of mesophyll cells isolated from the leaves of Zinnia elegans L. have been used extensively to investigate cellular processes involved in the differentiation of TEs (Fukuda and Komamine, 1985;Fukuda, 1989Fukuda, ,1992Seagull and Falconer, 1991). Here we report the influence of extracellular pH on cell expansion, as well as the timing of differentiation and the size and secondary cell wall pattem of resulting TEs.The effeds of medium pH on cell expansion and tracheary element (TE) differentiation were investigated in differentiating mesophyll suspension cultures of Zinnia elegans 1. In unbuffered cultures initially adjusted to pH 5.5, the medium pH fluduated reproducibly, decreasing about 1 unit prior to the onset of TE differentiation and then increasing when the initiation of new TEs was complete. Elimination of large pH fluctuations by buffering acid altered both cell expansion and TE differentiation, whereas altering the starting pH of unbuffered culture medium had no effed on either process. Cell expansion in buffered cultures was pH dependent with an optimum of 5.5 to 6.0. The direction of cell expansion was also pH dependent in buffered cultures. Cells elongated at pH 5.5 to 6.0, whereas isodiametric cell expansion was predominant at pH 6.5 to 7.0. The onset of TE differentiation was delayed when the pH was buffered higher or lower than 5.0. However, TEs eventually appeared in cultures buffered at pH 6.5 to 7.0, indicating that a decrease in pH to 5.0 is not necessary for differentiation. Very large TEs with secondary cell wall thickenings resembling metaxylem differentiated in cul...

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Carbon Dioxide and pH Requirements of Non‐Photosynthetic Tissue Culture Cells

Cited by 41 publications

References 15 publications

Ammonium Influence on the Growth and Nitrate Reductase Activity of Paul's Scarlet Rose Suspension Cultures

Ammonium Influence on the Growth and Nitrate Reductase Activity of Paul's Scarlet Rose Suspension Cultures

Acid-Growth Response and α-Expansins in Suspension Cultures of Bright Yellow 2 Tobacco

Cell Expansion and Tracheary Element Differentiation Are Regulated by Extracellular pH in Mesophyll Cultures of Zinnia elegans L

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