Senescence in Leaves of Acer pseudoplatanus L. and Parthenocissus tricuspidata Planch: 1. Changes in Some Leaf Constituents during Maturity and Senescence

Data are recorded of the changes in chlorophylls, carotene,sugar, shikimic acid, and anthocyanin in leaves of sycamore(Acer pseudoplatanus L.) and Virginia creeper (Parthenocissustricuspidata Planch.) during leaf maturity and senescence. InParthenocissus the losses of chlorophylls, carotene, sugar,and shikimic acid during senescence were closely correlated,and were inversely related to the accumulation of anthocyanin.The losses of chlorophylls, carotene, and sugar by Acer leaveswere also closely correlated. No evidence was found to supportthe suggestion that anthocyanin formation was caused by accumulationof sugar during senescence, but marked differences in shikimicacid content were found between leaves of Acer, which did notform anthocyanin, and Parthenocissus. which did. It is suggestedthat autumn senescence of these leaves involves the rapid senescenceof an increasing proportion of the leaf tissue during a periodof 80 days, and that measurements of the content of constituentsgive an estimate of the proportion of the leaf tissue whichhas senesced.     

Regeneration from Leaf Squares of Peperomia sandersii A .DC: a Relationship between Rooting and Budding

Evidence is presented to show that in leaf squares of Peperomiasandersii bud initiation does not occur independently of rooting.Buds were formed close to the point of origin of roots and,in treatments where rooting was delayed, budding was affectedsimilarly. Promotion of root formation by pretreatment of squareswith 3-indolylbutyric acid was accompanied by increases in thenumber of buds initiated. Kinetin and N⁶-benzyladenine whichinhibited the initiation of roots also inhibited the initiationof buds. This was in contrast to the effect of these two compoundson leaf squares of Begonia rex where rooting was similarly inhibitedbut bud initiation was markedly promoted. When leaf squaresof Peperomia were grown in contact with relatively high concentrationsof kinetin buds were occasionally formed in the absence of roots.Removal of roots from leaf squares of Peperomia by excisionprevented the formation of buds.     

Calcium-Dependent Lamina Production of Nymphoides peltata (Gmel.) O. Kuntze (Menyanthaceae): Implications for Distribution

Nymphoides peltata (Gmel.) O. Kuntze, a nymphaeid macrophyte,occurs commonly in polder and fluviatile areas in large partsof Europe and Asia. In contrast to the nymphaeid macrophytesNymphaea alba L. and Nuphar lutea (L.) Sm., Nymphoides peltatais almost completely absent from poorly-buffered waters andis never found in acid water bodies. Transplantation experimentsin water bodies of varying alkalinity demonstrated that, irrespectiveof the sediment type, leaf production of Nymphoides did occurin poorly-buffered waters, but not in acid waters. Cultivation experiments showed that floating leaf developmentof Nymphoides peltata could only take place if sufficient calciumwas available in the water layer or in twice-demineralized water.Addition of calcium to an acid cultivation medium or to watercollected from an acid moorland pool resulted in leaf production.Growth of Nymphoides in acid waters is impossible due to insufficientcalcium concentrations in the water layer of such waters. Itis suggested that the absence of Nymphoides peltata in somepoorly-buffered water bodies is partly due to the spatial isolationfrom rivers and canals and the high frequence of desiccation.The restricted occurrence of Nymphoides peltata to well-bufferedalkaline waters is functionally more related to the calciumavailability than to the bicarbonate content. Key words: Aquatic macrophytes, distribution, Nymphoides peltata, leaf production, calcium, acid, poorly-buffered and alkaline water     

PHYSIOLOGICAL ACTIVITIES OF HELMINTHOSPOROL AND HELMINTHOSPORIC ACID: I. EFFECTS ON GROWTH OF INTACT PLANTS

Helminthosporol (H-ol) and helminthosporic acid (H-acid) wereeffective in promoting elongation of leaf sheaths of rice, Japanesebarnyard grass and dwarf maize (d-2 and d-5) and of hypocotylsof taisai (Brassica chinensis), but inactive in leaf sheathsof oat and wheat, hypocotyls of sesame and morning glory (Pharbitisnil) and epicotyls of Pharbitis and dwarf and tall peas. Onthe elongation of the leaf sheath of maize d-1, H-ol was promotivebut the activity of H-acid was doubtful. On hypocotyls of lettuceand daikon (Raphanus sativus), only H-acid was active. Multiplicationrate and size of fronds of Lemna perpusila were not affectedby either of the substances. Compared with gibberellic acid for the effect on the shoot growth,H-ol and H-acid were weak in activity and narrower in the scopeof plants that responded. H-ol and H-acid characteristicallypromoted the elongation of the primary root. Comparative effectivenessof H-ol and H-acid varied with plant species or parts examined. ¹ This study was supported in part by grant-in aid of the Ministryof Education (No. 0417). The results reported here were presentedat the Annual Meeting of the Botanical Society of Japan at Kanazawain 1964 (S).     

Identification of a Water-soluble Fungal Inhibitor in the Leaves of Acer platanoides L.

It was confirmed that the leaves of Acer platanoides containan antifungal inhibitory substance. Low concentrations of sterilecold water extracts inhibited the germination of the sporesof Cladosporium herbarum (three isolates), Cladosporium sphaerospermumand Cylindrocarbon radiclcola. In the concentration range 0·06–0·125per cent (w/v) of leaf material the inhibitory response wasdemonstrated to increase linearly as the concentration of leafmaterial increased logarithmically. Inhibitory activity wasfound in leaf samples collected during a period from July toOctober but activity had disappeared from leaves collected inthe following January. The inhibitory activity was located intwo components of the water extract by bioassay tests followingether extraction and separation by chromatography. One of theactive components has been identified as gallic acid by gaschromatography. Gallic acid has also been detected in dew collectedfrom leaf surfaces where it is suggested that it may play animportant part in the colonization of the leaves by fungi.     

Distribution and Production of trans-Aconitic Acid in Barnyard Grass (Echinochloa crus-galli var. oryzicola) as Putative Antifeedant against Brown Planthoppers

A quantitative analysis of organic acid in leaves of barnyardgrass revealed that the contents of trans-aconitic acid werehigh, suggesting that this compound may act as an antifeedantagainst brown planthoppers. However, trans-aconitic acid couldnot be detected in the phloem sap which was considered to bethe main nutrient source for brown planthoppers. trans-Aconiticacid was formed in vitro from cis-aconitic acid through theaconitate isomerase activity which was detected only in theleaf sheath, but not in the leaf blade. (Received August 10, 1992; Accepted November 30, 1992)     

PHYSIOLOGICAL.STUDIES OF A CHIMAERA FORMED BY GRAFTING NIGHTSHADE UPON TOMATO I. RESPIRATORY ACTIVITY OF LEAVES

1. Leaves of a chimaera which are composed of the tissues fromLycopersicum esculentum var. kinnari (L. e.) covered by twolayers of cells from Solatium villosum (S. v.) were comparedwith those of control plants, L. e. and S. v. with respect tothe respiratory activity. 2. As for the respiratory activity of leaf strips, the chimaerawas more active than either L. e.. or S. v. 3. To respiratory inhibitors examined leaf strips of the chimaeraresponded rather similarly to those of S. v. but differentlyfrom those of L. e. 4. Of various substrates tested, glycolic, ascorbic and chlorogenicacids were actively oxidized by cell-free extracts of leavesfrom every plant. The first two were especially good substratesfor S. v.: L. e. attacked most the third, and the chimaera oxidizedjust as well the first two as S. v. did and the third as L.e. did. 5. Ascorbic acid and chlorogenic acid contents of the leaf extractswere not correlated with the activities of the extracts of oxidizingthese substances. 6. Physiological interactions were suggested between the twotissues of different origins in the chimaera. (Received December 2, 1963; )     

An Association Between Acid Invertase Activity and Cell Growth during Leaf Expansion in Phaseolus vulgaris L.

Changes in lamina area, dimensions of epidermal and palisadecells, acid invertase activity and content of sucrose and hexosein the primary leaves of Phaseolus vulgaris L. were determinedbetween emergence of the hypocotyl hook and the completion ofleaf expansion. Growth in area and thickness of the primaryleaf after emergence was attributable to the expansion of cellsalready present in the lamina at emergence. The major invertasein the expanding leaf was a readily soluble acid invertase;little insoluble invertase activity was detected. Soluble andinsoluble fractions of leaf homogenates contained little neutralinvertase activity. The specific activity of the soluble acidinvertase increased rapidly during the early stages of leafexpansion, reaching a peak at the time of most rapid cell enlargement(5 d after emergence) and then declining as the leaf matured.Highly significant positive correlations were found betweenenzyme specific activity and the rates of cell and leaf enlargement. The early, rapid phase of lamina expansion was characterizedby high concentrations of hexose sugar and low concentrationsof sucrose. As the rates of leaf cell enlargement declined theconcentration of hexose fell and that of sucrose increased.Between 5 d and 11 d after hypocotyl emergence, the hexose/sucroseratio in the primary leaf decreased approximately 10-fold asthe specific activity of acid invertase decreased. The results are discussed with reference to sources of carbonsubstrates for cell growth and to the sink/source transitionduring leaf development. Key words: Leaf expansion, Acid invertase, Hexose, Sucrose, Phaseolus     

Differences in Iron Nutrition Strategies of Two Calcifuges,Carex piluliferaL. andVeronica officinalisL.

Veronica officinalisandCarex pilulifera, widespread calcifugeplants in Europe, were cultivated in acid and calcareous soilsto study differences in Fe aquisition strategies indicated inprevious studies. The experiments were performed in a computer-controlledglasshouse at a soil solution moisture content of 50–60%water holding capacity; additional light was supplied at 70W m^-2if ambient light was <100 W m^-2between 0600 and 1800h.Both species developed chlorosis when grown in the calcareoussoil.C. piluliferaproved unable to translocate sufficient amountsof Fe to the leaves when cultivated in calcareous soil, butmuch Fe accumulated in, and especially as a precipitate on thesurface of roots. In contrast,V. officinalistended to increaseFe taken up into the leaves of plants grown on calcareous soil,but a much greater proportion of the leaf tissue Fe was accumulatedas less active forms not extracted by Fe complexing agents,e.g. 1,10-phenanthroline, than was the case in acid-soil grownplants. Considerably less Fe was accumulated in the root biomassofV. officinaliscompared toC. pilulifera.It is concluded thatchlorosis inC. piluliferais related to insufficient Fe uptakein the leaves, whereas leaf immobilization of Fe in physiologicallyless active forms is the problem inV. officinalis. Iron; chlorosis; calcifuge; iron immobilization; leaf tissue; fractionation; Carex pilulifera; Veronica officinalis     

Variation in Photosynthesis and Enzyme Activity in Cenchrus ciliaris L.

Populations of Cenchrus ciliaris differ significantly in relativegrowth-rate (R), net assimilation rate (E), and leaf-area ratio(F). Differences in R were related to differences in E ratherthan in F. The populations also differed in the rate of apparentphotosynthesis of individual leaves as measured by infra-redgas analysis. Warburg and ^l4CO₂ techniques. Temperature andlight-response measurements revealed optimum temperature forphotosynthesis of 35 °C and the rate in most populationscontinued to increase up to the highest levels of irradianceemployed (200 W m²). The relative order of the populations wassimilar in all methods of analysis, but there was no relationshipevident between leaf photosynthesis and E derived from growthanalysis. The activity of the enzyme PEP carboxylase, expressedin terms of unit leaf area, was correlated with photosyntheticrate of the leaf. Activities of PEP carboxylase and of proteinsynthesis in vitro expressed on a basis of soluble protein contentwere correlated with E, but no such relationship was found forthe enzymes acid phosphatase and alanine--ketoglutarate aminotransferase.     

Hormonal Control of Morphogenesis in Leaf Explants of Perilla frutescens Britton var. crispa Decaisne f. viridi-crispa Makino

Leaf discs of Perilla frutescens var. crispa f. viridi-crispawere cultured on a defined medium to investigate factors influencingbud and root formation, callus induction, somatic embryogenesis,and floral bud formation. Addition of naphthalene-acetic acid(NAA) to the culture medium caused compact callus whereas 2,4-dichlorophenoxyacetic acid (2,4-D) promoted soft and friable callus formationon the surface of the explants. Benzyladenine, when appliedwith auxin, suppressed callus and root formation. Somatic embryogenesisoccurred, when the explants were first grown on nutrient mediumcontaining 2,4-D and organic elements, and then transferredto the 2,4-D free medium. Treatments with cytokinins, N-phenyl-N'-(4-pyridyl)urea and its derivatives induced bud formation. A low concentrationof NAA and naphthoxy-acetic acid promoted bud development. Occasionalfloral bud formation was observed depending on the originalleaf positions on mother plants from which the leaf discs wereexcised. A gradient of floral bud forming capacity along thestem was noted. Perilla frutescens, tissue culture, embryogenesis, morphogenesis, benzyl adenine, kinetin, naphthalene-acetic acid, naphthoxy-acetic acid, 2,4-dichlorophenoxy acetic acid, indol-3yl-acetic acid, cytokinins, auxins     

Effect of Temperature on Growth of Crotalaria juncea L. and Crotalaria sericea Retz.

Growth performances of Crotalaria juncea L. and C. sericea Retz.have been compared at two controlled temperatures, 16–20°C, and 28–32 °C, with respect to increase ind. wt and leaf area, relative growth rate, leaf area ratio,specific leaf area, leaf weight ratio, net assimilation rate,the ratio of mean relative growth rate to mean relative rateof leaf area increase () and shoot/root ratios. Both the speciesgrew better at the higher temperature; however the relativegrowth rate was more affected by temperature in C. sericea thanin C. juncea. Further, it was observed to be more dependenton net assimilation rate than on the leaf area ratio. Crotalaria juncea L., Crotalaria sericea Retz., relative growth rate, leaf area ratio, specific leaf area, leaf weight ratio, leaf area increase, net assimilation rate, shoot/root ratio     

Abscisic Acid and the Regulation of Water Loss in Plantlets of Brassica oleracea L. var. botrytisRegenerated Through Apical Meristem Culture

Water loss was studied in regenerated plantlets of Brassicaoleracea var. botrytis cv. Currawong derived through apicalmeristem culture. Hardening of plantlets was eliminated by asingle application of a polyvinyl resin (S600) sprayed immediatelyafter transplanting. Plantlets sprayed with S600 had highercuticular resistances than unsprayed plantlets; this treatmenthad no effect on stomatal resistance. Leaves formed during theculture period showed very little wax formation and using markedleaves it was found that only reduced levels of wax formed onthese leaves even after transplanting. New leaves formed aftertransplanting, showed typical wax formation compared to seedgrown plants. Abscisic acid (ABA) at 10^–4 M applied as a leaf sprayto transplants did not cause a substantial increase in stomatalresistance in leaves which had been initiated during the cultureperiod. Leaves of seed-grown plants as well as leaves of plantletsformed after transplanting did respond to a leaf spray of ABAat 10^–4 M by a large increase in stomatal resistance. Relative concentrations of K, Na, Ca, P, S and Mg in guard cellswere calculated for each leaf type by X-ray micro-probe analysis.K/Na values decreased in the order: seedling > leaves formedafter transplanting > leaves intiated during culture. A highpositive correlation was also found between K/Na and K/P forthe three leaf types. K:Mg and K:Ca ratios for leaves formedduring culture were low in comparison to the values obtainedfor leaves formed after transplanting and seedlings for whichthe values were similar. Brassica oleracea var. botrytis, cauliflower, regenerated plantlets, meristem culture, stomatal resistance, water loss, abscisic acid, X-ray micro-probe analysis     

Ascorbic Acid Turnover in Cotton Boll as Affected by Foliar Application of Sucrose

Excision of main stem leaf subtending the sympodium decreasedascorbic acid turnover in the developing boll (cotton fruit)on the first node of this sympodium in var. Suvin Gossypiumbarbadense L). Ascorbic acid turnover increased substantiallyin seed cotton and carpels of the boll when sucrose was appliedto the source leaf even though the main stem leaf remained excised.The role of ascorbic acid if any in boll growth appeared tobe linked with sucrose transport. Ascorbic acid, sympodial leaf, sucrose, boll     

Early Leaf Development and Leaf Sheath Formation of Botrychium strictum and B. virginianum (Ophioglossaceae)

The morphogenesis of the leaf sheath was studied in Botrychiumstrictum and B. virginianum of subgenus Osmundopteris. In thetwo species, the leaf primordium is initiated on the lowestpart of a ridge which is formed by partial growth of the shootapex. The leaf primordium first grows to cover the shoot apexalmost entirely except for a slit-like opening. The openingis formed by the frontal rim of the growing leaf primordium,i.e. the leaf margin, and the rear part of the shoot apex. Asthe leaf grows, the leaf margin elongates and takes a reverseV-shape. On both lateral edges of the leaf margin, marginalgrowth occurs to form the lobes of the leaf sheath. Such marginalgrowth and a small amount of growth on the uppermost portionof the sheath is involved in the leaf sheath formation in B.cirginianum, while only marginal growth takes place in B. strictum.The leaf sheath of Botrychium virginianum, in comparison tothat of B. strictum, has a morphogenesis which is more similarto the completely covering leaf sheath of subgenera Botrychiumand Sceptridhim. Based on the morphogenesis of the leaf sheath,systematic relationships in subgenus Osmundopteris are discussed Botrychium virginianum, B. strictum, subgenus Osmundopteris, leaf ontogeny, leaf sheath formation, scanning electron microscopy, light microscopy     

Cuticular permeability of the three tree species Prunus Iaurocerasus L., Ginkgo biloba L. and Juglans regia L.: comparative investigation of the transport properties of intact leaves, isolated cuticles and reconstituted cuticular waxes

Cuticular transport properties of intact leaves, isolated cuticularmembranes and reconstituted cuticular waxes of the three treespecies Prunus laurocerasus L., Ginkgo biloba L. and Juglansregia L. were measured using six different ¹⁴C-labelled compounds,benzoic acid, salicylic acid, 2,4-dichlorophenoxy acid, metribuzin,4-nitrophenol, and atrazine. For the same compound and the samespecies, the permeance of the intact leaf and the isolated cuticlewas equal. This provides strong evidence demonstrating thattransport properties of cuticles are not altered during isolation.Additionally, diffusion coefficients of the ¹⁴C-labelled compoundsin isolated and subsequently reconstituted cuticular wax ofthe three tree species were measured. Permeances of intact leavesand isolated cuticles could be predicted from diffusion coefficients,wax/water partition coefficients and the thickness of the transport-limitingwax layer with a mean deviation of about 1.7. This providesevidence that transport properties of recrystallized cuticularwaxes do indeed reflect barrier properties of isolated cuticularmembranes and intact leaves with in situ waxes. Thus, it canbe concluded that the investigation of cuticular permeabilityusing the three independent experimental systems of differentcomplexity give comparable results. Finally, it was observedthat permeances and diffusion coefficients measured with P.laurocerasus were always significantly lower than those measuredwith G. biloba and J. regia. This is interpreted as an ecologicaladaptation of the respective species. The evergreen speciesP. laurocerasus must be more adapted to environmental stresssuch as drought and frost injury compared to the two deciduousspecies G. biloba and J. regia. Key words: Cuticular permeability, diffusion coefficient, leaf surface, permeance, plant cuticle, transport     

The importance of linoleic acid and linolenic acid as precursors of hexanal and trans-2-hexenal in black tea

During tea fermentation, linoleic acid in the neutral fat fraction,and linolenic acid in both the neutral fat and phospholipidfractions from leaves decreased. The addition of linoleic orlinolenic acid to leaf macerates during fermentation resultedin an increase in hexanal or trans-2-hexenal in the volatilefraction. Tracer experiments showed the direct conversion oflinoleic-U-¹⁴C and linolenic-U-¹⁴C acids to labeled hexanaland trans-2-hexenal, respectively, which were identified as2,4-DNPH derivatives. Further conversion of hexanal and trans-2-hexenal into hexanoicand trans-2-hexenoic acids during tea fermentation was suggestedby the increases in these compounds after the addition of hexanaland trans-2-hexenal to leaf macerates. (Received December 21, 1971; )     

An 15N -- 14C Study of the Role of the Leaf in the Nitrogen Nutrition of the Seed of Datura Stramonium L.

¹⁵N-Nitrate feeding via the transpiration stream and simultaneousfeeding of ¹⁴C via photosynthesis to a leaf-fruit system inD. stramonium indicate that glutamine is the prime recipientof photosynthetically reduced nitrogen in the leaf. Analysisof petiole and seed indicates that glutamine supplies the seedwith most of the reduced nitrogen required for amino acid synthesis.Carbon and nitrogen assimilation in the leaf do not appear tobe directly related in that serine and aspartate and not glutaminereceive the heaviest initial ¹⁴C label.     

Effect of the Rht3 dwarfing gene on dynamics of cell extension in wheat leaves, and its modification by gibberellic acid and paclobutrazol

The second leaf of wheat was used as a model system to examinethe effects of the Rht3 dwarfing gene on leaf growth. Comparedto the rht3 wild type, the Rht3allele decreased final leaf length,surface area and dry mass by reducing the maximum growth rates,but without affecting growth duration. Gibberellic acid (GA₃)increased final leaf length and maximum growth rate in the rht3wild type, but was without effect on the Rht3 mutant, whichis generally regarded as being non-responsive to gibberellin(GA). Paclobutrazol, an inhibitor of GA biosynthesis, decreasedfinal leaf length and maximum growth rate in the rht3 wild typeto values similar to those in the untreated Rht3 mutant. NeitherGA₃ nor paclobutrazol affected the duration of leaf growth.The decrease in leaf length was produced by reduction of celllength rather than cell number. The maximum relative elementalgrowth rate (REGR) for cell extension was essentially the samein all treatments, as was the time between the cells leavingthe meristem and achieving maximum extension rate. The differencesbetween the genotypes and treatments were all almost entirelydue to differences in the time taken from the attainment ofmaximum REGR of cell extension to the cessation of extension.This was reflected in the length of the extension zone, whichwas approximately 6–8 per cent of final leaf length. Theeffects of the Rht3 allele, GA₃ and paclobutrazol all appearto be on the processes which promote the cessation of cell elongation. Key words: Cell extension, gibberellin, leaf growth, Rht3 gene, Triticum, wheat     

Effects of Soil Temperature on the Growth and Hormone Content of Dactylis glomerata L. (Cocksfoot) in Controlled Environments

A comparison was made of effects of ‘low’ and ‘high’soil temperature (LST and HST, about 9 and 21·5 °Crespectively) on shoot growth of Norwegian and Portuguese populationsof Dactylis glomerata. In experiments lasting 8 short days (SD,8 h photoperiods) LST decreased leaf extension more markedlyin the Portuguese population. No differential effect of LSTon leaf growth was recorded in experiments lasting 20 or 21SD or in experiments of 8 d duration in long days (LD, 16 hphotoperiods). Since the meristem and region of cell extensionis close to the soil surface LST could directly influence bothroot and shoot growth. The application of gibberellic acid enhanced leaf extension,particularly in plants grown at HST. 6-Benzylaminopurine tendedto decrease leaf length. Extractable gibberellin levels wererelatively low after 8 SD in shoots of both races grown at LST.Cytokinin levels increased at LST, more so in shoots of Portugueseplants which sustained the greater reduction in leaf extension. The data suggest that LST may reduce the production of endogenousgibberellins important for leaf growth in Dactylis glomerata.Cytokinins are probably necessary for growth processes but theirlevel may reflect, rather than direct, the rate of leaf growth.