bluuebunny/crossref_metadata_2025_split huggingface dataset:
EVIDENCE FOR THE PARTICIPATION OF GLUTAMATE DEHYDROGENASE IN AMMONIUM ASSIMILATION BY STICHOCOCCUS BACILLARIS
Authors: EVEREST S. A. , SYRETT P. J. 
Published: May 2006

SummaryCells of the green alga, Chlorella vulgaris (strain 21l/8k) have high NADPH‐glutamate de‐hydrogenase (GDH) activity when grown on ammonium (NH4+); activity is low in nitrate (NO3−)‐grown or nitrogen‐depleted cells. In contrast, cells of Stichococcus bacillaris (strain 379/5) contain little NADPH‐GDH activity when grown on NH4+ but much when grown on NO3− or depleted of nitrogen. Despite the high NADPH‐GDH activity in NH4+‐grown cells of C. vulgaris, NH4+ assimilation by this organism is strongly inhibited by methionine sulphoximine (MSO), an inhibitor of glutamine synthetase. NH4+ assimilation by NH4+‐grown S. bacillaris is similarly almost completely inhibited by MSO. However, NH4+ assimilation by NQ3‐grown S. bacillaris is much less inhibited by MSO and it is suggested that the high NADPH‐GDH activity of these cells is partly responsible for the remaining NH4+ assimilation.
HYBRIDIZATION, PGLYPLGIDY AND APOMIXIS IN ANDROPOGON TECTORUM SCHUM. AND THONN. (GRAMINEAE)
Authors: OKOLI BOSA E. 
Published: May 2006

SummaryNatural populations of Andropogon tectorum from various parts of Nigeria have been investigated and found to contain diploid and triploid chromosome races. Intraspecific hybrids were obtained between two morphologically and cytologically distinct diploids. Meiosis in the triploids was characterized by a high frequency of univalents in one collection and of multivalents in another. At meiosis in the diploid hybrid, multivalents and non‐disjunction ‘bridge‐and‐fragment’ configurations were discovered. The triploid collections and the hybrids were observed to reproduce apomictically. The relationship between hybridization and polyploidy on the one hand and apomixis on the other is examined in the light of the available information.
CRYSTALS OF CALCIUM COMPOUNDS IN GRAMINEAE
Authors: LERSTEN NELS R. 
Published: May 2006

SummaryFrom reviews of the anatomy and cell contents of grasses it would appear that crystals of calcium compounds do not occur. However, 13 scattered reports of such crystals in grasses have been discovered in the literature. As a result of observations made by the author, calcium oxalate crystals have been found in bundle sheath cells and adjacent mesophyll in leaves of Melinis minutiflora (Panicoideae).
DO LEMON COTYLEDONS GREEN IN THE DARK?
Authors: WHATLEY JEAN M. , PRICE D. N. 
Published: May 2006

SummaryIn general angiosperms do not synthesize chlorophyll in the dark. It has, however, been pointed out that the large or woody fruits of a few species may be opaque, but that, nevertheless, their embryos become green. In some species of citrus, seeds occasionally germinate within the intact, ripe fruit. The cotyledons of such seedlings expand and become dark green. An electron microscope investigation showed that the cotyledons contained chloroplasts with few stroma lamellae but with true grana. The quality of light reaching the seeds and embryos in ripe lemons was found to be poor in blue light but rich in the red wavelengths necessary for the conversion of protochlorophyll to chlorophyll. The quantity of light penetrating to the embryos was low but of an order of magnitude known to be adequate for chlorophyll synthesis and chloroplast development in a number of species.
CONTACT ANGLES OF WATER DROPLETS ON NEEDLES OF SCOTS PINE (PINUS SYLVESTEIS) GROWING IN POLLUTED ATMOSPHERES
Authors: CAPE J. N. 
Published: May 2006

SUMMARYContact angles of 1 μl droplets of distilled water were smaller on old than young needles of Pinus sylvestris. The decrease from c. 110° on young needles was larger for needles of trees growing in atmospheres with c. 40 μ SO2 m−3 than for those from trees in atmospheres with < 10 μg SO2 m−3 (c. 70° and c. 80° respectively on 3‐year‐old needles). Although there were small changes in the wettability of the needle cuticle, the decreases in contact angle are largely attributable to changes in epicuticular waxes.
THE ADAPTIVE ARCHITECTURE OF SHRUB CANOPIES: LEAF DISPLAY AND BIOMASS ALLOCATION IN RELATION TO LIGHT ENVIRONMENT
Authors: NICOLA A. , PICKETT S. T. A. 
Published: May 2006

SUMMARYLeaf display features and biomass allocation were investigated in four dominant shrubs of forest and old‐field habitats in central New Jersey, USA, to determine whether differences exist between species which reach optimum development in different successional environments. Late‐successional shrubs were found to possess larger leaves, greater leaf area expansion (ratio of leaf area to leaf weight), and increased allocation of total energy to leaves versus wood, compared to early‐successional shrubs. The shrubs appeared to deviate from patterns of biomass allocation expected in trees, possibly as a result of relative ease of horizontal exploitation of space through cloning. In addition, there appears to be a great deal of flexibility in features of leaf display which may play an important role in shrub adaptation to particular light regimes.
EFFECTS OF FLOODING ON LEAF WATER POTENTIAL AND STOMATAL RESISTANCE INBRUGUIERA GYMNORRHIZA(L.) LAM
Authors: NAIDOO G. 
Published: May 2006

SUMMARYThe effects of 10, 20, 40 and 80 days of flooding on stomatal responses in the halophyte,Bruguiera gymnorrhiza(L.) Lam were investigated. Measurements were made of leaf water potential and stomatal resistance (rg) during the period of flooding, and continuing for 12 to 14 days after its termination.Generally, plants flooded for prolonged periods had lower leaf water potentials than the controls both during and after flooding. Prolonged flooding also resulted in higherrgduring flooding and continuing for 8 to 10 days afterwards. Leaf water potentials decreased with increase in the duration of flooding. Decrease in leaf water potential was also associated with an increase inrg.Prolonged flooding also resulted in ultrastructural modifications. The chloroplasts had smaller grana and the lamellae were considerably swollen. There also appeared to be some degradation of thylakoid membrane structure.
PRODUCTIVITY OF FIELD‐GROWN SOYBEANS EXPOSED TO SIMULATED ACIDIC RAIN
Authors: EVANS LANCE S. , LEWIN KEITH F. , PATTI MITCHELL J. , CUNNINGHAM ELIZABETH A. 
Published: May 2006

SUMMARYTwo experiments were performed during the summer of 1981 to determine the effects of simulated acidic rain on seed yields of soybeans grown using standard agronomic practices. In one experiment, plants were shielded from all ambient rainfall and exposed to simulated rainfall in quantities equal to the average amount of rainfall that occurs at the site. Seed yields of soybeans exposed twice weekly to simulated rain of pH 4.1, 3.3 and 2.7 were, respectively, 10.7, 16.8 and 22.9 % below yields of plants exposed to simulated rain of pH 5.6. A treatment‐response function of seed yield vs rainfall pH was y= 7.40 +1.025x and had a correlation coefficient of 0.997 (y is seed mass per plant and x is the pH of the simulated rain). In a second experiment, soybean plants were not shielded from ambient rainfall (weighted mean hydrogen ion concentration equal to pH 4.04) and received only small volumes of simulated rainfall three times weekly. Plants exposed to simulated rainfall of pH 4.1, 3.3 and 2.7 exhibited yield reductions of 2.7, 7.0 and 7.6%, respectively, below yields of plants exposed to simulated rainfall of pH 5.6. By best fit analyses, the equation describing this relationship is expressed by y= 9.68 + 0.318x, and the correlation coefficient is 0.97. In both experiments, the observed decrease in seed yields was due to a decrease in number of pods per plant.
ULTRASTRUCTURE OF ACTIVE AND DORMANT CAMBIAL CELLS IN TEAK (TECTONA GRANDIS L. f)
Authors: RAO K. S. , DAVE Y. S. 
Published: May 2006

SUMMARYCytological changes in the ultrastructure of cambial cells of teak (Tectona grandis) during active and dormant periods have been studied after glutaraldehyde‐osmium tetroxide fixation. The fusiform and ray initials are essentially alike in their ultrastructure and all have cellular organelles. Active cambial cells are highly vacuolated and are rich in all organelles. They contain rough endoplasmic reticulum (ER), polysomes, dictyosomes with hypertrophied cisternae, mitochondria and plastids with starch. The plastids are characterized by the presence of varying amounts of a dark intralamellar inclusion which is considered to be a protein. Microfilament bundles, 0.05 to 0.2 üm in width, occur frequently in the parietal cytoplasm. Dormant cambial cells have numerous small vacuoles, smooth ER, free ribosomes and a few inactive dictyosomes. In addition to the dark inclusion, plastids contain what are thought to be phytoferritin granules and prolamellar bodies. Branched plasmodesmata and paramural bodies are associated with the cambial cell walls.
DIFFERENTIATION OF THE PHOTOSYNTHETIC APPARATUS IN PHYLLITIS SCOLOPENDRIUM (L.) NEWMAN
Authors: MARIANI COLOMBO P. , RASCIO N. , CASADORO G. 
Published: May 2006

SUMMARYChloroplast development in both coiled and uncoiling croziers of Phyllitis scolopendrium has been studied. An interesting stage of chloroplast ontogenesis appears to be that characterized by the presence of very long thylakoid stacks. It resembles the final stage of organization attained by the chloroplasts of many green algae at maturity even if, in P. scolopendrium, it represents only an intermediate stage in thylakoid system ontogenesis.Growing the plants in the dark has a pronounced effect on the morphogenesis of the frond and on plastid differentiation. In both dark‐ and light‐grown plants we could observe, even if in different amounts, prolamellar body‐like structures interconnected with the thylakoids. The presence of such structures is discussed, especially in view of the fact that ferns are able to synthesize chlorophylls in the dark.
THE INFLUENCE OF LIGHT QUALITY ON CARBOHYDRATE TRANSLOCATION WITHIN CORN LEAF STRIPS
Authors: HODDINOTT J. 
Published: May 2006

ABSTRACTTo test the effect of light quality on carbohydrate translocation, leaf strips of Phaseolus vulgaris L. cv. Black Valentine were prepared before or after exposure to a 48 h dark pretreatment. Central portions of the strips were labelled with 14CO2 and translocate was allowed to move acropetally and basipetally along the strips. The portions of the strips on either side of the labelling region were exposed to red or far‐red light, or darkness. Translocation in darkened strips was predominantly basipetal. When portions of the strips were given red light, translocation to that region was suppressed. It is suggested that Ptr does not promote unloading. Pr formation induced by far‐red light, or dark decay of phytochrome, promotes unloading and long distance transport in a high irradiance response, but does not alter the normal polar transport in the strips.
EFFECT OF KINETIN AND CYCLIC 3′, 5′‐ADENOSINE MONOPHOSPHATE ON BUD INDUCTION IN THE MOSS TIMMIELLA ANOMALA
Authors: KAPOOR (néeREKHI) ANITA , CHOPRA R. N. 
Published: May 2006

SUMMARYKinetin enhances bud formation in Timmiella anomala. Cyclic 3′, 5′‐adenosine monophosphate (cAMP) and theophylline inhibit bud formation, but stimulate growth of gametophores. N8, O2‐dibutyryl adenosine 3′, 5′‐cyclic monophosphate has no appreciable effect. ATP, ADP, 2′, 3′‐cAMP, 5′‐AMP, adenosine and adenine stimulate bud formation. Kinetin in combination with cAMP further increases bud number and also the length of gametophores. This effect appears to be specific, since it is not observed when kinetin is added along with 2′, 3′‐cAMP, 5′‐AMP or adenosine.
MERCURY VAPOUR: A HEALTH HAZARD IN HERBARIA
Authors: BRIGGS D. , SELL P. D. , BLOCK M. , I'ONS R. D. 
Published: May 2006

SUMMARYMetallic mercury vapour is released from herbarium specimens poisoned with mercuric chloride, in quantities which might constitute a health hazard. By increasing the ventilation in the Cambridge University Herbarium, the concentration of mercury vapour in the air has been reduced to a safer level. Even if herbaria no longer use mercuric chloride to protect specimens against insect attack, botanists might wish to consider the health hazard involved by release of mercury from older herbarium specimens which might have been poisoned in the traditional manner.
POTATO INTRODUCTIONS AND BREEDING UP TO THE EARLY 20TH CENTURY
Authors: GLENDINNING D. R. 
Published: May 2006

SUMMARYFollowing an outline of the great variation in the primitive cultivars and wild species of potatoes in Latin America, the history of introductions and breeding procedures is discussed. Although two introductions occurred in the 16th century there were only few early introductions, and only very few varieties were grown in the early 18th century. The appearance of virus diseases, which debilitated established varieties but did not pass through true seed, led to widespread selection among seedlings and a vast increase in the number of varieties grown in the late 18th and early 19th centuries. The seedlings were from naturally‐set berries and most would be selfed derivatives; selection among them may have reduced the gene‐pool.Improvements made by this selection were such that most 19th century introductions appeared primitive and, with only two known exceptions, they were discarded. Blight appeared in the mid 19th century and eliminated almost all varieties, including a number which were probably virus resistant, thus further reducing the gene‐pool.T. A. Knight commenced deliberate crossing before 1810 but this practice did not become widespread until the second half of the 19th century. Breeding among the few survivors of the blight epidemics and the few new introductions led, by the early 20th century, to a great many varieties being grown, e.g. over 500 in Britain and over 50 in North America, but they represented only a very limited gene‐pool.The pedigrees of modern potato varieties show that, although several 20th century introductions may occur in their ancestries, generally 80% or more of their genes are derived from varieties grown early this century. An appendix illustrates this for the recent varieties Pentland Dell and Croft. It follows that the gene‐pool is still rather limited, and that modern varieties are somewhat inbred due to relationships between their parents and ancestors.
BIOCHEMICAL AND PHYSIOLOGICAL ASPECTS OF LEAF DEVELOPMENT IN COCOA (THEOBROMA CACAO L.)
Authors: ABO‐HAMED S. , COLLIN H. A. , HARDWICK K. 
Published: May 2006

SummaryThe flush leaves of seedling cocoa plants were assessed at each stage of the flush cycle from leaf unfolding to maturity for differences in leaf lamina presentation angle, surface hairs, stomatal number and development and leaf cuticle thickness. Changes in these parameters were then correlated with cuticular and stomatal diffusive resistance of the leaves. It is suggested that perpendicular positioning of the young flush leaves, the presence of surface hairs, the rapid synthesis of the cuticle and the limited stomatal development during the early stages of leaf expansion, restrict water loss from the developing leaves. Maximum rate of water loss from the leaves of a new flush was only attained after leaves were fully expanded, stomata fully developed and the leaves horizontally positioned. It is suggested that the large increase in water loss from the flush leaves following these changes might lead to an internal water deficit in the plant and hence to increased synthesis of abscisic acid in the shoot which, in turn, will maintain dormancy of the shoot apex in at least part of the interflush period.
AN ULTRASTRUCTURAL STUDY OF RESERVE LIPID MOBILIZATION IN STEM ROOT PRIMORDIA AND POPLAR
Authors: ČIAMPOROVá MILADA 
Published: May 2006

SummaryStructural aspects of reserve lipid mobilization have been investigated in cells following the initiation of rhizogenesis from root primordia in stem cuttings of poplar. The number of spherosomes decreases during the first hours of initiation indicating that the reserve lipids are utilized during rhizogenesis. The lipid is removed from some spherosomes in the cytoplasm, the other spherosomes being incorporated into the vacuole. Cytochemical reactions show that the cells of root primordia do not contain glyoxysomes. The process of reserve lipid utilization differs from that in germinating seeds in both the absence of glyoxysomes and the participation of vacuoles in lipid degradation.
THE MECHANISM OF ROOT CONTRACTION IN GYMNARRHENA MICRANATHA, A DESERT PLANT
Authors: ZAMSKI E. , UCKO ORNA , KOLLER D. 
Published: May 2006

SummaryThe taproot of the ephemeric desert annual Gymnarrhena micranatha (Asteraceae) starts to contract soon after emergence and continues to do so at a constant rate over a period of 50 days or longer. This causes retraction of the main shoot apex from the soil surface to a depth of about 10 mm. Contraction takes place in cells of the endodermis, pericycle and primary phloem which expand radially while contracting longitudinally to about one‐half their initial length. This results in a wavy pattern in their radial walls. Partial hydrolysis of the cell wall is probably associated with secretion of multivesicular bodies from the cytoplasm. Contracted cell walls appear wavy where dissolution is incomplete or straight with undulated microfibrils where it is more complete.
VANADIUM AS A TRACE ELEMENT IN THE BLUE‐GREEN ALGA, NOSTOC MUSCORUM: INFLUENCE ON NITROGENASE AND NITRATE REDUCTASE
Authors: VAISHAMPAYAN A. 
Published: May 2006

SummaryMolybdenum (Mo), a group VI B element (applied in the form of sodium molybdate at a concentration of 0.0177 ppm), is required for the nitrogenase and nitrate reductase activities of Nostoc muscorum and hence for growth on N2 and NO−3. These enzymic activities, as well as the growth of Mo‐containing cultures, are significantly enhanced by the addition of 0.0125 ppm vanadium (V), an element belonging to group V (applied in the form of sodium vanadate). At concentrations above 0.0125 ppm. V addition inhibits nitrogenase and nitrate reductase activities and ultimately leads to a retardation of growth on N2 and NO−3. Molybdenum and/or V has no effect on the growth of N. muscorum with NO−2 as nitrogen source.
PLANT‐INDUCED CHANGES IN THE RHIZOSPHERE OF RAPE (BRASSICA NAPUS VAR. EMERALD) SEEDLINGS
Authors: HEDLEY M. J. , NYE P. H. , WHITE R. E. 
Published: May 2006

SummaryAdditions of soluble phosphate to P‐deficient Begbroke sandy loam delayed or completely prevented the fall in rhizosphere pH observed when rape was grown at high root densities in this soil (Parts I to III, this series). Whereas the pH of the unamended rhizosphere soil fell from 6–6.5 to 5.1–5.3 by day 41, the rhizosphere pH of soil with an extra 2 μmol P g−1 remained steady (6 to 6.5) until day 35, and that of soil with an extra 20 μmol P g−1 increased slightly from pH 6 to 6.4 during 41 days of growth. The increase in rhizosphere phosphatase activity with increasing severity of P deficiency appeared to be a response to increasing root density and decreasing concentration of soluble inorganic P in the soil. No significant change in levels of soil organic P was detected.Plants that acidified their rhizosphere (low P status) depleted acid‐soluble forms of soil P and absorbed twice the amount of P which could be desorbed from the control soil in 10−2 M Ca(NO3)2at pH 6.1. Uptake of P by plants which did not acidify their rhizosphere (high P status) was never greater than the amount of P desorbable in 10−2m Ca(NO3)2 at pH 6.1, and was derived from alkali‐soluble and resin‐extractable forms of soil P. Cation uptake exceeded anion uptake in both low and high P plants, but the difference was greater in low P plants. These differences in cation and anion uptake (mEq) were approximately equal to the milliequivalents of H+ (OH−) required to produce the observed changes in rhizosphere pH. These results explain why models for P uptake based on in vitro measurements of physicochemical parameters governing phosphate diffusion in soil work well for P sufficient plants, but tend to underestimate P uptake by P deficient plants growing in soils in which soluble P levels are sensitive to pH change.
THE ROLE OF ECTOMYCORRHIZAS IN DROUGHT TOLERANCE OF DOUGLAS‐FIR SEEDLINGS *
Authors: PARKE ENNIFER L. , LINDERMAN R. G. , BLACK C. H. 
Published: May 2006

SummaryExperiments were conducted to test the relative ability of mycorrhizal and non‐mycorrhizal Douglas‐fir [Pseudotsuga menziesii(Mirb.) Franco] seedlings to tolerate and recover from drought conditions, using reduction in CO2fixation as an overall indicator of plant moisture stress. Seedlings were watered daily or conditioned to cyclic drying and re‐wetting of the soil. Net photosynthetic rates of mycorrhizal and non‐mycorrhizal seedlings watered daily did not differ significantly; however, drought‐stressed mycorrhizal seedlings fixed CO20at a rate ten times that of non‐mycorrhizal seedlings. Total leaf water potentials of mycorrhizal plants were lower (more negative) than those of non‐mycorrhizal plants but they recovered more rapidly.Non‐mycorrhizal seedlings and seedlings inoculated with four ectomycorrhizal fungus species were allowed to become desiccated, then were rewatered and compared for their ability to tolerate and recover from drought. Seedlings inoculated withRhizapogon vintcolorwere less affected by drought than any of the other mycorrhizal or non‐mycorrhizal treatments. Net photosynthetic rate ofRhizopogon‐inoculated seedlings 24 h following re‐watering was seven times that of non‐mycorrhizal seedlings. The transpiration rate ofRhizopogon‐inoculated seedlings was low before desiccation, declined rapidly during the drought period and, after re‐watering, quickly resumed a rate higher than that for other treatments.
USE OF VESICULAR‐ARBUSCULAR MYCORRHIZAL ROOTS, INTRARADICAL VESICLES AND EXTRARADICAL VESICLES AS INOCULUM *
Authors: BIERMANN BRENDA , LINDERMAN R. G. 
Published: May 2006

SummaryThe presence of intraradical vesicles increases the inoculum potential of excised mycorrhizas. High infectivity was obtained with root pieces colonized by species of vesicular‐arbuscular (VA) mycorrhizal fungi that formed intraradical vesicles (i.e. Glomus fasciculatum, Glomus mosseae and Acaulospora spinosa). Root pieces colonized by mycorrhizal fungi which generally do not form intraradical vesicles (i.e. Gigaspora margarita and Gigaspora gigantea) were not infective. Extraradical vesicles of Gigaspora margarita were also not infective propagules. Intraradical vesicles separated from the colonized roots remained highly infective but hyphae and cell debris from the same roots were not. Mycorrhizal fungi in root pieces treated for short times in sodium hypochlorite were apparently killed.
A PROCEDURE FOR ISOLATION OF SINGLE‐SPORE CULTURES OF CERTAIN ENDOMYCORRHIZAL FUNGI
Authors: FANG YU‐CHENG , McGRAW A.‐C. , MODJO HAKAM , HENDRIX J.W. 
Published: May 2006

SummaryA procedure for the isolation of single‐spore cultures of endomycorrhizal fungi is described. A single spore is placed on plant roots with a Pasteur pipette by use of a binocular microscope, and the plant is transplanted into sand in a 50 ml growth tube. Plants are incubated for 6 to 8 weeks in a greenhouse and are continuously subirrigated by capillarity with dilute (5 to 10%) Hoagland's solution. Forty to 80% of plants inoculated by this technique with single spores of Glomus macrocarpus, G. etunicatus and G. caledonius became infected. Cultures of G. constrictus and G. microcarpus were not obtained. Hoagland's solutions of up to 25% were equally effective for isolating G. macrocarpus, but limiting plant size by using only 5 or 10% Hoagland's solution was advantageous. The presence of spores on living root systems was the most reliable indicator of fungal development. Non‐inoculated control plants incubated in a common Hoagland's solution reservoir with inoculated plants never became mycorrhizal. The procedure uses readily available materials, is easy to use in the laboratory and conserves greenhouse space and labour.