The biological activities of 26 gibberellins in nine plant bioassays

Crozier, Alan; Kuo, C. C.; Durley, Richard C.; Pharis, R. P.

doi:10.1139/b70-121

Cited by 166 publications

(46 citation statements)

References 22 publications

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“…5). Fractions II and III, while active in the dS corn assay, probably escaped detection in the pea bioassay (16) since GA3 is the most active GA in this test (2,5). In subsequent experiments, Radley (17) (Fig.…”

Section: Discussionmentioning

confidence: 93%

Effects of Photoperiod on Growth Rate and Endogenous Gibberellins in the Long-Day Rosette Plant Spinach

Zeevaart

1971

Plant Physiol.

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The earliest visible responses of spinach plants (Spinacia oleracea L., cv. Savoy Hybrid 612) transferred from short to long days (8 hours of high intensity light supplemented with 16 hours of low intensity illumination from incandescent lamps) were upright leaf orientation and increased elongation of the petioles. The effect of long days on growth rate was direct; i.e., there was no after-effect if the plants were transferred to short days. Gibberellin A3 applied to plants under short days had an effect similar to that of long days, whereas application of the growth retardant AMO-1618 [2'-isopropyl-4'-(trimethylammonium chloride)-5'-methylphenyl piperidine-I-carboxylate] under long days caused a growth habit typical of short-day conditions. Gibberellin A3 caused more stem growth in plants under long days in which the endogenous gibberellin content had been reduced by AMO-1618 than in plants under short days not treated with the growth retardant.Three gibberellin-like substances, called I, II, and III in order of increasing RF value, were present in acidic extracts of spinach under short days. After transfer to long days, II increased, whereas I and III decreased, the latter below the level of detection in the d5 corn assay. Following application of AMO-1618 the gibberellin content of plants under long days fell off more rapidly than in those under short days, indicating that gibberellin turnover was markedly higher under long days. This increased rate of gibberellin metabolism was established after 2 long days. When plants were returned to short days, the turnover of gibberellins declined. It is suggested that a higher rate of gibberellin biosynthesis combined with increased sensitivity to gibberellin is responsible for the observed growth responses in spinach under long days.In many rosette LDP,1 application of GA under SD conditions causes stem elongation and flower formation (4, 11, 26). These observations have led to the idea that rosette plants on SD are deficient in GAs, while LD would raise the level of endogenous GAs which in turn would stimulate stem growth e.g., Ref. crease over the SD control by more than a factor of 2. However, results of diffusion experiments suggested that just prior to the onset of stem elongation both the biosynthesis of GA and its metabolism had increased.Working with spinach, Radley (16) reported a sharp although transient increase in GA content after 1 LD. She suggested that the decrease in GA level after more LD cycles was due to greatly increased turnover of GA. In view of this marked increase in the GA content after 1 LD, the levels of native GAs in spinach have been reinvestigated under different photoperiods, as well as the decrease in GA content following the application of the growth retardant AMO-1618. The results in this communication provide experimental support for the notion that the turnover of GAs in spinach is much higher under LD than under SD conditions. Preliminary reports of this investigation have been presented earlier (26, 27). MATERIALS AND METH...

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Section: Discussionmentioning

confidence: 93%

Effects of Photoperiod on Growth Rate and Endogenous Gibberellins in the Long-Day Rosette Plant Spinach

Zeevaart

1971

Plant Physiol.

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“…Dwarf rice cv Tan-ginbozu is, however, the most sensitive GA bioassay available and detects a broad spectrum of GA structures (3,20). It is also highly responsive to GA3, GA5, GA7, and GA32, which are among the most effective GAs for floral induction in L. temulentum.…”

Section: Resultsmentioning

confidence: 99%

Gibberellins, Endogenous and Applied, in Relation to Flower Induction in the Long-Day Plant Lolium temulentum

Pharis¹,

Evans²,

King³

et al. 1987

Plant Physiol.

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Changes in endogenous gibberellin-like substances (GAs) and related compounds in the shoot apices of Lolium temukntum during and after flower induction by one long day was examined for plants grown in three consecutive years. The total GA level in the shoot apical tissue was high (up to 42 mirograms per gram dry weight, or 3 x 10' molar GA3 equivalents) increasing several-fold on the day after the long day and then declning. Of the many GA-like substances present, the putative polyhydroxylated components-with HPLC retention times between those ofGAs (three hydroxyls) and GA32 (four hydroxyls), and accounting for about a quarter of the total GA activity-were most consistent and striking in their changes. Their level in the apices increased 3-to 5-fold on the day after the long day and then subsided. When varous GAs were applied to plants in noninductive short days, flower initiation was induced by several, most notably by GA32, GAs, 2,2-dimethyl GA4, GA3, and GA7. GA32 was most like one long day in eliciting a strong flowering response while having little effect on stem growth, whereas GA, had the opposite effect. It is suggested that highiy hydroxylated C-19 GAs may play a central role in the induction of flowering in this long-day plant. action (30).Many different endogenous GAs are found in plants, and changes in their concentration in shoot tissue occur following vernalization or photoperiodic induction, e.g. in spinach (28) and Agrostemma (11). Metzger and Zeevaart (18) have proposed that the conversion of GA,9 to GA20 in spinach is under photoperiodic control and conclude that the increase in GA20 is the cause of bolting in spinach, whereas in Agrostemma all the endogenous GAs underwent a transient increase following transfer to LD, associated with stem elongation (11).In the LDP Lolium temulentum, applications of GA3 and several other gibberellins induced flowering under noninductive SD. However, the growth retardant CCC did not prevent LD induction as it did in Samolus; in fact it substantially enhanced rather than reduced the effect of applied GA3 (4, 5) and a comparable response has been found in another LDP, Blitum spp. (10).In this paper, we present evidence for some of the changes in the endogenous GAs of L. temulentum during photoperiodic induction by a single LD, emphasizing the highly polar GAs in the true shoot apex, for which few data are available. These findings have led us to examine the effects of applications of several GAs, notably GA32, the results of which indicate very different specificities for stem growth on the one hand and for flower initiation on the other.Several kinds of evidence implicate the GAs2 in the initiation of flowering in photoperiodically sensitive plants. Applications of GA3 and other GAs replace the requirement for LD or low temperature vernalization in many species (22,29). With the LDP Samolusparviflorus, inhibitors ofGA synthesis can prevent flower initiation, this inhibition being reversed by application of GA3 (l). Applied GAs also replace the need for ...

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“…26 In the germinating grain, cell wall degradation starts adjacent to the embryo and spreads in a broad band from the face of the scutellum. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] cates that at the onset of germination p-glucanases are secreted by the scutellar epithelium. Later, cell wall degradation is observed beneath the aleurone layer, which also seems to secrete p-glucanases.8-26'51 This is evident especially in grains treated with gibberellic acid.…”

Section: Breakdown Of Cells Wallsmentioning

confidence: 99%

Mobilisation of Endospermal Reserves During the Germination of Barley

Enari

Sopanen

1986

Journal of the Institute of Brewing

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The metabolism of the germinating barley seed is a complicated physiological process. From the point of view of industrial malting, the syntheses of amylolytic and proteolytic enzymes as well as the degra dation of endospermal structures are extremely important. In order to control his process the maltster needs to have a good understanding of these processes as well as of the regulatory mechanisms which control them. When a good malting barley is allowed to germinate under traditional conditions for the time needed, a good malt can be produced without this scientific background. The present day brewing industry, however, has to work with barleys which are not of the traditional malting type and further more accelerated processes are an economic necessity. Under these circumstances, the maltster needs all scientific help he can get. Biochemical and physiological research on germination provides him with the tools he needs for process control and optimisation.

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The biological activities of 26 gibberellins in nine plant bioassays

Cited by 166 publications

References 22 publications

Effects of Photoperiod on Growth Rate and Endogenous Gibberellins in the Long-Day Rosette Plant Spinach

Effects of Photoperiod on Growth Rate and Endogenous Gibberellins in the Long-Day Rosette Plant Spinach

Gibberellins, Endogenous and Applied, in Relation to Flower Induction in the Long-Day Plant Lolium temulentum

Mobilisation of Endospermal Reserves During the Germination of Barley

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