Zur Regulation der RNS-Synthese durch Phytochrom bei der Photomorphogenese des Senfkeimlings (Sinapis alba L.)

Summary P₇₃₀, the active phytochrome, increases the rate of RNA synthesis (Table) and the RNA contents in the cotyledons of the mustard seedling (Sinapis alba L.) (Fig. 1) whereas the RNA contents in the hypocotyl is decreased under the influence of P₇₃₀ (Fig. 2).—It takes about 6 hours until changes in the RNA contents-which must be attributed to the formation of P₇₃₀—can be measured after the onset of light (continuous far-red). Since the lag-phases of positive photoresponses in the cotyledons and negative photoresponses in the hypocotyl (Mohr, 1966) are in general much shorter than 6 hours, the changes of the RNA contents of the organs cannot be regarded as being directly connected with the formation of characteristic positive photoresponses such as anthocyanin synthesis, induced enzyme synthesis, ascorbic acid synthesis, etc., or negative photoresponses such as inhibition of hypocotyl lengthening.We have rather to conclude that the changes of RNA contents are secondary adaptations of the organs which lead to an increase (cotyledons) or decrease (hypocotyl) of protein synthesizing capacity of the cells and tissues. The P₇₃₀-dependent increase of bulk RNA in the cotyledons is probably due to a differential gene activation and the P₇₃₀-dependent decrease of bulk RNA in the hypocotyl is due to a differential gene repression. The causalities of these processes are possibly complex.The hypothesis of differential gene activation or repression by P₇₃₀ (Mohr, 1966; Schopfer, 1967a, b) is not disproved by these results. We have rather to reach a conclusion which has already been suggested by other data (e.g. Karow and Mohr, 1966), namely, that positive as well as negative photoresponses are due to changes in the activity of a limited (possibly small) number of enzymes. Correspondingly changes in only a minute amount of the total RNA are directly involved in the formation of photoresponses. These changes cannot be detected by following RNA contents.—It seems to be of great interest, however, that P₇₃₀ eventually brings about strong tissue specific changes in the RNA contents per cell as described in the present paper.     

Die Zellwandzusammensetzung von Hypokotylen des Senfkeimlings (Sinapis alba L.) bei Wachstumshemmung durch Inhibitoren oder Phytochrom

Summary During inhibition of hypocotyl elongation in the mustard seedling by actinomycin D, hydroxyproline, and continuous far-red via phytochrome 730 the synthesis of cell-wall carbohydrates is impaired in the same manner. Independent of the treatment 12 hrs after its beginning at a relative inhibition of hypocotyl elongation of 80–90% the relative inhibition of the cell-wall carbohydrate content is uniformly about 30–35%. No significant quantitative nor apparent qualitative differences in the sugar and uronic acid content of the pectic, hemicellulosic, and -cellulosic cell-wall fraction could be detected.     

Die Steigerung der durch Phytochrom bewirkten Anthocyansynthese des Senfkeimlings (Sinapis alba L.) durch Chloramphenicol

Zusammenfassung Chloramphenicol (CAP) steigert in einem gewissen Konzentrationsbereich (etwa 20–40 g/ml) die durch Dunkelrot (DR) ausgelöste Anthocyansynthese des Senfkeimlings. Die lag-Phase sowie der Zeitpunkt der Beendigung der Anthocyansynthese werden durch das Antibioticum nicht beeinflußt. Mit und ohne CAP beobachtet man bei allen untersuchten DR-Intensitäten eine konstante Akkumulationsrate an Anthocyan über einen Zeitraum von mindestens 24 Std. —Die Steigerung der Akkumulationsrate durch CAP (20 g/ml) liegt stets im Bereich von 25%, auch wenn die DR-Intensität auf die Hälfte oder ein Viertel gesenkt wird (Wirkung des CAP=25% · Wirkung des DR). Man kann daraus formal schließen, daß CAP und DR unabhängig voneinander die Anthocyansynthese beeinflussen. Molekular läßt sich der Sachverhalt folgendermaßen deuten: CAP hemmt bei einer Konzentration von 20 g/ml die Proteinsynthese der Plastiden. Dadurch wird der Phenylalanin-pool in den Kotyledonen erhöht. Da diese geringe CAP-Konzentration die cytoplasmatische Proteinsynthese noch nicht hemmt, kann die Anthocyansynthese ungestört ablaufen. Da Phenylalanin als eine Vorstufe der Flavonoidsynthese fungiert, führt das erhöhte Angebot an dieser Substanz zu einer Steigerung der Anthocyansynthese.

---

The increase of phytochrome-mediated anthocyanin synthesis in the mustard seedling (Sinapis alba L.) by chloramphenicol

Summary Chloramphenicol (CAP) within a certain range of concentration (about 20–30g/ml) increases the rate of far-red mediated anthocyanin accumulation in the mustard seedling (Sinapis alba L.) (Fig. 1). The lag-phase after the onset of far-red and the time of termination of anthocyanin synthesis are not influenced by the presence of the antibiotic (Fig. 2). With and without CAP we observe a constant rate of anthocyanin accumulation over a period of at least 24 hours after the lag-phase at all far-red intensities investigated (Fig. 2). The percentage increase of the rate of anthocyanin accumulation which is due to CAP (20 g/ml) is independent of the far-red intensity applied and always amounts to about 25% (Table). Formally one can conclude that CAP and far-red seem to act as two independent factors in a multiplicative system. On the molecular level the observations can possibly be explained as follows: CAP at a concentration of 20 g/ml inhibits protein synthesis of the plastids. This inhibition leads to an increase of the pool of phenylalanine in the cotyledons. Because the small concentration of CAP does not interfere with protein synthesis (enzyme synthesis) in the cytoplasm, far-red mediated anthocyanin synthesis can proceed normally. Since phenylalanine acts as a precursor of flavonoids the increased pool of this substance will lead to an increase in the rate of anthocyanin accumulation.

     

Die Wirkung von Phytochrom und Actinomycin D auf die Chlorophyll a-Synthese von Senfkeimlingen (Sinapis alba L.)

Zusammenfassung Eine Vorbestrahlung der etiolierten Senfkeimlinge mit 4 Std Dunkelrot bewirkt eine Steigerung der Chlorophyll a-Synthese im Weißlicht. — Andererseits wird die Chlorophyll a-Synthese bereits durch relativ niedrige Actinomycin D-Konzentrationen gehemmt oder verzögert. — Die hemmende Wirkung von Actinomycin D ist — ausgedrückt in Prozent Hemmung — mit und ohne Vorbelichtung genau dieselbe. Auch die übrigen Daten deuten darauf hin, daß Actinomycin D nicht auf die Protochlorophyllsynthese als solche wirkt, sondern vielmehr die Synthese bestimmter Strukturproteine in den Plastiden beeinträchtigt. —Die Daten der Arbeit werden genphysiologisch gedeutet. Der wesentliche Punkt dabei ist, daß aktive Gene (z.B. jene, welche die Enzyme der bekanntlich auch im Dunkeln ablaufenden Protochlorophyllsynthese codieren) relativ unempfindlich gegenüber Actinomycin D sind; potentiell aktive Gene hingegen (z.B. jene, die einige nur im Licht entstehende spezifische Strukturproteine der Plastiden codieren) scheinen sehr viel empfindlicher gegenüber Actinomycin D zu sein. Diese Schlüsse stehen im Einklang mit einer früher geäußerten Hypothese (Lange und Mohr, 1965) und mit den Daten von Schopfer (1966) über die Regulation der Ascorbatsynthese im Senfkeimling durch Phytochrom und Actinomycin D.

---

The action of phytochrome and actinomycin D on chlorophyll a formation in mustard seedlings (Sinapis alba L.)

Summary In the mustard seedling chlorophyll a synthesis under white light is enhanced by a pretreatment with far-red which maintains a low but virtually stationary concentration of active phytochrome (=P₇₃₀) (Fig. 1) during the period of irradiation (4 hours). — On the other hand chlorophyll a synthesis is inhibited or delayed by relatively low concentrations of Actinomycin D(=Act) (Fig. 2)The inhibitory action of Act (on a percent basis) is exactly the same with and without a far-red pre-irradiation (Fig. 3). Act in relatively low doses (5 or 10 g/ml) greatly extends the lag-phase of chlorophyll synthesis; however, these doses do not influence the effect of the far-red pretreatment on the rate of chlorophyll synthesis when it finally takes place (Fig.4,5,6). The data presented in this paper indicate that Act does not inhibit protochlorophyll synthesis as such; we have rather to conclude that Act inhibits the de novo synthesis of some specific structural proteins which are prerequisites of chlorophyll accumulation and maintenance in the plastids (Table 1). Synthesis of these structural proteins seems to be under the control of phytochrome too.It is concluded that those genes which are already in function are relatively resistant to Act (e. g. those genes which are needed for protochlorophyll synthesis) whereas potentially active genes (e. g. those which code some specific structural proteins of the plastids) are very sensitive to Act. —A similar conclusion has been reached in an earlier paper in connection with phytochrome-induced antocyanin synthesis (Lange and Mohr, 1965). Our argumentation is further supported by Schopfer's data on control of ascorbate synthesis in the mustard seedling by phytochrome and Act (Schopfer, 1966).

     

Der DNS-Gehalt von Kotyledonen und Hypokotyl des Senfkeimlings (Sinapis alba L.) bei der phytochromgesteuerten Photomorphogenese

Zusammenfassung Der DNS-Gehalt und somit auch die Zellzahl von Kotyledonen und Hypokotyl des Senfkeimlings sind zwischen 36 und 60 Std nach Aussaat sowohl im Dunkel als auch im Dunkelrot weitgehend konstant. Die durch Phytochrom bewirkte Zunahme des RNS-und Proteingehaltes (Weidner u. Mitarb., 1965) muß deshalb als eine RNS-bzw. ProteinZunahme pro Zelle aufgefaßt werden. Dieser Befund stützt die Vorstellung einer differentiellen Genaktivierung durch P₇₃₀ (z.B. Mohr, 1966).—Die weitgehend konstante Zellzahl von Hypokotyl und Kotyledonen während des von uns verwendeten Experimentierzeitraumes ist eine wichtige Voraussetzung für die Vergleichbarkeit biochemischer Daten, z.B. bei kinetischen Studien (vgl. Mohr, 1966).

---

The DNA contents of cotyledons and hypocotyl of the mustard seedling (Sinapis alba L.) during phytochrome-mediated photomorphogenesis

Summary DNA contents and accordingly cell numbers of cotyledons and hypocotyl of the mustard seedling were virtually constant during the experimental period (between 36–60 hours after sowing) in the dark as well as under the influence of P₇₃₀, the active phytochrome (Table).—Therefore the phytochromemediated increase of the RNA and protein contents (Weidner et al., 1965) must be understood as an increase of RNA and protein per cell. This fact is in agreement with the conception of differential gene activation mediated by P₇₃₀ (Mohr, 1966). The virtually constant DNA contents during the period of time which is regularly used for experimentation on photomorphogenesis in our laboratory (36–60 hours after sowing; Mohr, 1966) is an important prerequisite for comparing biochemical data under the point of view of differential gene activation, e.g. in kinetical studies in the dark and under continuous far-red light.

     

Streckungshemmung durch FUDR bei den Hypokotylen von Sinapis alba

Summary Seedlings of Sinapis alba which were grown in light for 24, 48 and 72 h after 36 h of dark treatment renew elongation when transferred to dark again. The rate of elongation decreases with increased light treatment. The per cent as well as absolute inhibition of elongation by FUDR decreases with the duration of light treatment. The shortening of the hypocotyl is due mainly to the inhibition of cell elongation. The inhibition is not directly proportional to DNA synthesis at any particular time.Plants without cotyledons are less inhibited than those with cotyledons. Cytosine arabinoside is inhibitory only at high concentrations. According to these results elongation inhibition by FUDR does not involve the entire DNA-synthesis.     

Untersuchungen zur Energetik der phytochrominduzierten Photomorphogenese des Senfkeimlings (Sinapis alba L.)

Zusammenfassung Im Zusammenhang mit der Energetik der Photomorphogenese wurden Trockenmasse, Fettgehalt und Verbrennungswärme zu Beginn und Ende des Versuchszeitraums bestimmt und die Kinetik der Sauerstoffaufnahme und Kohlendioxidabgabe aufgenommen. DR-Dauerbestrahlung verschiebt das Maximum der O₂-Aufnahme und CO₂-Abgabe auf einen späteren Zeitpunkt und führt insgesamt zu einer Steigerung des Gasstoffwechsels. Fettabbau und Energieabgabe werden ebenfalls gesteigert, obwohl die Syntheseleistungen des Keimlings (gemessen als fettfreie Trockenmasse bzw. deren Verbrennungswärme) geringer sind als bei den Dunkelkontrollen. Für das Absinken der Ausbeute während der Photomorphogenese werden verschiedene Erklärungsmöglichkeiten angegeben.Eine theoretische Ableitung zeigt, daß der relative Meßfehler bei der indirekten manometrischen Methode gegenüber der direkten Methode mit abnehmendem respiratorischen Quotientem immer größer wird.

---

Investigations on the energetics of phytochrome mediated photomorphogenesis in mustard seedlings (Sinapis alba L.)

Summary To characterise the energetics of whole seedlings of Sinapis alba L. during photomorphogenesis under continuous far-red light, measurements were made (between 36 and 72 hours after sowing) of changes in dry weight, fat content, heat of combustion, O₂ uptake and CO₂ evolution in irradiated and dark treated control plants. Irradiation caused a delay in the time of maximum O₂ uptake and CO₂ evolution and led to an increase in the total gaseous metabolism. Likewise, the rates of breakdown of fats and release of energy were increased; this occurred even though the total synthesising capacity of the seedlings, as measured by fat free dry weight or by heat of combustion of fat free dry matter, was lower in the farred irradiated seedlings than in the dark controls. Thus, during the course of photomorphogenesis the yield of plant material, as measured by the increase in fat free dry matter divided by the decrease in fat, or by the increase in heat of combustion of fat free dry matter divided by the decrease in heat of combustion of fat, was markedly reduced (approximately 60%). Several possible explanations were put forward to account for this reduction, but lack of thermodynamic data allowed none to be favoured.Theoretical considerations showed that the experimental error associated with measurements of gaseous metabolism was always larger when the indirect manometric method rather than the direct method was used. This effect was more pronounced the higher the respiratory quotient was.

     

Kinetische studien zur Interpretation der Wirkung von Sukzedanbestrahlungen mit Hellrot und Dunkelrot bei der Photomorphogenese (Anthocyansynthese bei Sinapis alba L.)

Zusammenfassung In einer früheren Arbeit (Bertsch und Mohr, 1965) haben wir bei der lichtinduzierten Anthocyansynthese des Senfkeimlings gefunden, daß eine Vorbestrahlung mit Dunkelrot die Wirkung einer nachfolgenden Bestrahlung mit Hellrot steigert. Eine Vorbestrahlung mit Hellrot hingegen reduziert die Wirksamkeit einer nachfolgenden Bestrahlung mit Dunkelrot (Tabelle 1). Die 48 St nach Beginn des Bestrahlungsprogramms vorhandene Menge an Anthocyan wurde als ein Maß für die Wirksamkeit der Sukzedanbestrahlungen angesehen. — In der vorliegenden Arbeit wurde mit Hilfe kinetischer Studien gezeigt, daß ein spezifischer Effekt der Dunkelrot-Vorbestrahlung nicht existiert. Der apparente Effekt ist darauf zurückzuführen, daß das zuerst gegebene Dunkelrot die lag-Phase für das nachfolgende Hellrot eliminiert. — Der Effekt, daß eine Hellrot-Vorbestrahlung die Wirkung von nachfolgendem Dunkelrot stark reduziert, ist hingegen real. Dieser Effekt muß auf einen Verlust an Phytochrom zurückgeführt werden.

---

Kinetical studies to interpret the effects of succedaneous irradiations with red and far-red on photomorphogenesis (anthocyanin synthesis in mustard seedlings, Sinapis alba L.)

Summary In a previous paper (Bertsch and Mohr, 1965) we reported that in light-induced anthocyanin synthesis of the mustard seedling (Sinapis alba L.) a preirradiation with far-red light increases the effectiveness of a following irradiation with red light, whereas a preirradiation with red reduces the effectiveness of a following irradiation with far-red (Table 1). The amount of anthocyanin present 48 hours after the onset of the irradiation programme was taken as a gauge for the effectiveness of the irradiation with succedaneous red and far-red (and vice versa).In the present paper it is shown—using detailed kinetical studies (Fig. 1 and 2) —that a specific potentiating effect of the preceding far-red is not involved. The apparent effect is due to the fact that the preceding far-red eliminates the lag-phase for the following red (Fig. 1). — On the other hand, the depressing effect of red light preceding far-red is very real. This latter effect must be attributed to a loss of phytochrome.We demonstrate in the present paper that the effects of succedaneous red and far-red irradiations can be attributed altogether to phytochrome if several assumptions concerning the stability of phytochrome 730 (Hartmann, 1966; Wagner and Mohr, 1966) are made. These assumptions seem to be well justified. — In any case our kinetical studies have revealed no data which indicate that in red or far-red light we have to deal with anything else except phytochrome.

     

Nachweis der Phytochrom-induzierten de novo-Synthese von Phenylalaninammoniumlyase (PAL,E.C.4.3.1.5) in Keimlingen von Sinapis alba L. durch Dichtemarkierung mit Deuterium

Summary Using the in vivo density labeling technique with deuterium oxide it is confirmed that during phytochrome mediated photomorphogenesis in mustard seedlings a true de novo synthesis of phenylalanine ammonia-lyase is induced by active phytochrome (P _fr).     

Elektronenmikroskopischer Nachweis des Virus der Milden Rübenvergilbung (beet mild yellowing virus) in der Wirtspflanze Sinapis alba L

Abstract

Thomasius, H. (Herausg.) Wald, Landeskultur und Gesellschaft 2. überarb. Auflage., 466 S., 122 Abb., Jena: VEB Gustav Fischer Verlag 1978. Reviewed by S. Prien.

W. W. Djoshkin: Leben und Umwelt 1. Auflage, 205 S. 21 Abb. Moskau/Leipzig/Jena/Berlin: Mir/Urania 1978. Reviewed by W. Tarnow.

Ahrens, G. Giftgesetz und Giftverkehr 386 S., Leipzig: Johann Ambrosius Barth 1979. Reviewed by H. Kleinhempel.

Schliephake, G.; Klimt, K.: Die Tierwelt Deutschlands — Thysanoptera, Fransenflügler 1. Aufl., 477 S. 66. Teil, 528 Abb,. Jena: VEB Gustav Fischer Verlag 1979. Reviewed by Th. Wetzel.

Fröhlich, G. (Herausg.): Phytopatologie und Pflanzenschutz 295 S., 62 Abb., Jena: VEB Gustav Fischer Verlag 1979. Reviewed by R. Fritzsche.

Lyr, H.; Polter, C. (Hrsg.): Systemfungizide 371 S., zahlr. Abb., Berlin: Akademie-Verlag 1979. Reviewed by K. Naumann.

Mohamed Ali Mohamed Ali: Ecological and Physiological Studies on the Alfalfa Ladybird 200 S., zahlr. Abb., Budapest: Akadémiai Kiado 1979. Reviewed by R. Fritzsche.

Piffl, E. (Ed.): Proceedings of the 4th International Congress of Acarology 752 S., zahlr. Abb., Budapest: Akadémiai Kiado 1979. Reviewed by R. Fritzsche.

Godan, D.: Schadschnecken und ihre Bekämpfung 467 S., 203 Abb. Stuttgart: Eugen Ulmer Verlag 1979. Reviewed by R. Fritzsche.     

白芥自交亲和性分析

对不同来源的8份白芥材料,采用人工自交法分析其自交亲和性。结果显示:白芥的自交亲和性存在较大幅度的变异,自交亲和指数在0.01~4.10之间,8份参试材料中,自交亲和指数小于1的材料有3个,自交亲和指数大于1的材料有5个。表明白芥中存在自交亲和材料,白芥自交亲和性变异不仅存在于材料间,而且也存在于同一材料内不同个体间。按自交亲和指数的高低,可将参试材料分为3种类型:高自交亲和类型(自交亲和指数大于3.00,如民乐洪水芥麻、04(X)等)、自交亲和类型(自交亲和指数为1.00~2.99)、自交不亲和类型(自交亲和指数0.00~1.00)。     

Phytochrome-regulated Expansion of Mustard (Sinapis alba L.) Cotyledons

In developing mustard (Sinapis alba L.) seedlings continuousred light acting via the agency of phytochrome stimulates therate of expansion of cotyledons. Although phytochrome actionon cotyledon expansion is evident only after 36 h from sowing,the photoresponse escapes from reversibility at about 15 h fromsowing. The time lag of 21 h between loss of photoreversibilityand the onset of photoregulated cotyledon expansion indicatesthe existence of long-lived components in the phytochrome-triggeredsignal chain. Phytochrome-regulated cotyledon expansion doesnot require the involvement of photosynthesis, as applicationof SAN 9789, an inhibitor of chloroplast biogenesis, did notaffect cotyledon expansion. The role of turgor pressure-relatedcellular parameters such as osmotic potential () cell wall extensibility(m), hydraulic conductivity (L) and yield threshold (Y) forcell expansion were examined during photoregulated cotyledonexpansion. Using the general equation of cell growth dv/dt =[Lm/(L+m)]( - Y), where dv/dt is the rate of volumetric growth,it was demonstrated that the light-mediated cotyledon expansionresults from an increase in cell wall extensibility (m). Theseresults are discussed in relation to the photoregulation ofcotyledon expansion. Key words: Cell wall extensibility, growth, Sinapis alba L., phytochrome