Virtual Issue Articles: Introduction to a Virtual Special Issue to mark the publication of the 200th volume of New Phytologist Effect of gibberellic acid on the growth and anatomy of Coleus blumei, Antirrhinum majus and Salvia splendens J. M. Bostrack, B. E. Struckmeyer The osmotic strength of cell sap in plants growing under different conditions E. Drabble, H. Lake
Comparison of the effects of a localised supply of phosphate, nitrate, ammonium and potassium on the growth of the seminal root system, and the shoot, in barley M. C. Drew The influence of light on stomatal density in the tomato A. P. Gay, R. G. Hurd A theory of plant geography R. D’O. Good The effect of wind on plant growth and soil moisture relations: a re-assessment A. W. Humphries, F. J. Roberts Carbohydrate physiology of mycorrhizal roots of beech. III. Movement of sugars between host and fungus D. H. Lewis, J. L. Harley
Mechanisms of plant survival and mortality during drought: why do some plants survive while others succumb to drought? N. McDowell, W. T. Pockman, C. D. Allen, D. D. Breshers, N. Cobb, T. Kolb, J. Plaut, J. Sperry, A. West, D. G. Williams, E. A. Yepez
Stomata and hydathodes in Campanula rotundifolia L., and their relation to environment M. W. Rea Physiological mechanisms of drought-induced tree mortality are far from being resolved A. Sala, F. Piper, G. Hoch
The symptoms of calcium deficiency in plants E. W. Simon Stelar evolution in vascular plants B. F. Slade The ‘xerophytic’ character of the Gymnosperms. Is it an ‘ecological’ adaptation? M. C. Stopes The problems of ecology A. G. Tansley Xerophytic adaptations of bryophytes in relation to habitat W. Watson The effect of wind on plant growth and soil moisture relations: a reply to the re-assessment by Humphries and Roberts F. H. Whitehead Effect of light intensity during growth on leaf anatomy and subsequent light-saturated photosynthesis among contrasting Lolium genotypes D. Wilson, J. P. Cooper
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Introduction To mark the publication of the 200 th volume of New Phytologist, Editor-in-Chief Alistair Hetherington has invited two of his predecessors, Peter Ayres and Ian Woodward, to personally select articles that they deem to be significant from the journal’s archive. The selected papers have been grouped together to form this Virtual Special Issue (VSI). A special Editorial has been written to accompany the collection, which places these papers in an historical, and where possible, a contemporary context. Selecting a small number of articles for inclusion in this VSI was no easy task, and a diverse group of papers with a publication span from 1904 to 2010 is presented in this collection. The articles selected by Professors Ayres and Woodward have not been chosen to cover the entire scope of the journal, but nonetheless, they typify the enduring nature of the research published in New Phytologist over 200 volumes, and illustrate how papers published in some cases over 100 years ago are as relevant today as they were upon first publication. This collection is a reflection upon a rich and illustrious history, however, the focus of New Phytologist is firmly on the future. The journal continues to publish the very best in ground -breaking science and is leading the way in technological advancements in publishing, becoming a fully online-only journal in 2012. In addition, the New Phytologist Trust is committed to supporting and nurturing the next generation of plant scientists.
All of the papers included in this VSI are freely available without subscription. The New Phytologist Trust ensures that all New Phytologist content is free to view one year after publication and that all Tansley reviews and Forum articles are free to access as soon as they are published. We hope that this collection will inspire readers to explore the journal’s archive as well as our current content, where they will find seminal research works alongside an unparalleled collection of authoritative review articles, letters and commentary.
Article Effect of gibberellic acid on the growth and anatomy of Coleus blumei, Antirrhinum majus and Salvia splendens
J. M. Bostrack, B. E. Struckmeyer
Summary New Phytologist (1967) 66: 539 – 544 doi: 10.1111/j.1469-8137.1967.tb05425.x
Plants of Coleus blumei (Coleus), Antirrhinum majus (snapdragon) and Salvia splendens (Salvia) exhibited three common responses to foliar applications of 50 mg/l aqueous solution of gibherellic acid (GA); elongation of the internodes, hyponasty and chlorosis. Elongation of subapical internodes was a result primarily of cell division in both Antirrhinum majus and Salvia splendens. Gibberellic acid at 500 mg/l caused less elongation of the sub-apical region than at 50 mg/l and 100 mg/l in S. splendens. Treated plants had a smaller stem diameter and more xylem parenchyma. Coleus blumei cuttings showed reduced rooting when treated with 50 mg/l GA.
Article The osmotic strength of cell sap in plants growing under different conditions
E. Drabble, H. Lake
New Phytologist (1905) 4: 189 - 191 doi: 10.1111/j.1469-8137.1905.tb05901.x
Comparatively few observations on the osmotic strength of cell sap in plants growing under different physical conditions seem to have been made. The most familiar is probably Mr. Francis Darwin's determination for the Dandelion, given in his " Practical Physiology of Plants." The method employed by him consisted in cutting the inflorescence-stalk longitudinally and placing strips of the stalk in pure water. This resulted in curvature of the strips in an outward direction—i.e., the cells occupying the inner face of the strip expanded more than those occupying the outer face, owing largely to the mechanical arrangement of the tissues in these regions. The curled strips were then placed in solutions of potassium nitrate of known strengths, and the solution in which the strip retained the same degree of curvature was taken as isotonic with the cell sap. This method gives very accurate determinations of the strength of the sap, but is only applicable in relatively few cases. A method involving observation of the plasmolysis of the cells can however be very generally applied. By this means a number of plants have been examined with regard to the strength of their cell sap.
Article Comparison of the effects of a localised supply of phosphate, nitrate, ammonium and potassium on the growth of the seminal root system, and the shoot, in barley M. C. Drew
Summary New Phytologist (1975) 75: 479 - 490 doi: 10.1111/j.1469-8137.1975.tb01409.x
Barley plants were grown for 21 days in sand culture, continuously irrigated with nutrient solution. The rooting depth was divided into three compartments, one above another, such that different zones of the root system could be supplied with very low or high concentrations of a single inorganic nutrient, all other nutrients being maintained at a high concentration. Exposure of parts of the main seminal roots (axes) to high concentrations of phosphate caused a localized promotion of the initiation and subsequent extension of both first and second order laterals, compared with zones receiving very low concentrations of phosphate. This resulted in considerable modification to root form, but with only a small depression in shoot growth, compared with control plants receiving an ample supply to all parts of the root system. The extension of seminal axes was little affected by the concentration of phosphate to which they were exposed. Similar responses to those described for phosphate occurred with variation in concentration of nitrate or ammonium, but with potassium a localized supply promoted the growth of laterals to approximately the same extent as controls throughout the entire root system. The experiments show that adequate external concentrations of nitrogen and phosphorus are required by any part of the root system for optimal growth of laterals, but not axes. Possible mechanisms which compensate shoot growth when nutrients are supplied to only part of the root system, and agronomic implications, are discussed.
Article The influence of light on stomatal density in the tomato
A. P. Gay, R. G. Hurd
Summary New Phytologist (1975) 75: 37 - 46 doi: 10.1111/j.1469-8137.1975.tb01368.x
Stomatal densities (stomatal number per unit leaf area) were determined on tomato plants grown at ‘high’ (100 W m−2 ) and ‘low’ (20 W m−2 ) light in a growth cabinet. The upper epidermis of a fully expanded leaf in low light had fewer than one stoma mm−2 , whilst that in high light had thirty stomata mm−2 . On the lower epidermis there were about eighty and 100 stomata mm−2 in low and high light respectively. Similar differences were observed on plants growing in natural light. Stomatal initiation is most active early in the development of the leaf and effects of light on initiation were greatest at this stage, being observable within 3 days of a change in light level. Since light influenced the rate and duration of all stages of leaf expansion, the final stomatal densities achieved under natural conditions varied with the light history of the leaf. Stomatal density reached a peak before the leaf had expanded to 10% of its final area. Stomatal initiation and stomatal density both decreased from then until leaf expansion ceased. Fully-expanded leaves of plants grown continuously in the same environment had similar stomatal densities irrespective of their position on the plant. A quantitative relationship is described between stomatal density and leaf area during the growth of a leaf.
Article A theory of plant geography
R. D’O. Good
Introduction New Phytologist (1931) 30: 149 doi: 10.1111/j.1469-8137.1931.tb07414.x
In the course of some years' work on the geographical distribution of the Angiosperms, I have paid particular attention to certain theoretical aspects of the subject. More especially have I endeavoured to discover the principles underlying the processes of distribution in order to use them as a basis for a working hypothesis capable of explaining the chief features of Angiosperm geography.
Up to the present I have come to certain conclusions which, although doubtless incomplete, nevertheless appear to me sufficiently interesting and useful to warrant their publication. Briefly these results are as follows: first, the recognition that six general statements (set out below) are so incontrovertible that they may reasonably be regarded as basic principles: second, the fact that these principles satisfactorily form the framework of a general hypothesis of plant distribution provided that an additional theory, relating to their inter-relationships, is acceptable: third, the presentation of such a theory under the name of "The Theory of Tolerance.�
Article The effect of wind on plant growth and soil moisture relations: a re-assessment
A. W. Humphries, F. J. Roberts
Summary New Phytologist (1965) 64: 319 – 322 doi: 10.1111/j.1469-8137.1965.tb05401.x
The argument that wind and soil moisture stress induce similar anatomical changes in plant leaves, and that these changes enhance the ability of the plant to restrain water loss, is examined. It is shown that the data presented by Whitehead (1963a) can be explained satisfactorily in terms of induced changes in root distribution and leaf area, without invoking any specialized adaptations for the reduction of water loss.
Article Carbohydrate physiology of mycorrhizal roots of beech. III. Movement of sugars between host and fungus
D. H. Lewis, J. L. Harley
Summary New Phytologist (1965) 64: 256 - 259 doi: 10.1111/j.1469-8137.1965.tb05395.x
In order to test the relevance of previous results of this series to conditions operative in the intact plant, a technique was devised to simulate translocation of sucrose to mycorrhizal roots and to determine its morphological and biochemical destinations by the use of [14C]sugar. It was shown that the fungus can absorb sugar from the host and that its chemical destination is essentially similar to that of exogenous sucrose, namely a synthesis of mannitol, trehalose and glycogen. In connection with the possibility of reciprocal flow from fungus to host, the ability of uninfected roots to utilize the soluble sugars of the fungus was tested. Whereas mycorrhizas readily absorb and metabolize mannitol and trehalose, uninfected roots have almost no ability to utilize mannitol and are restricted in their utilization of trehalose, throwing considerable doubt on the possibility of sugar absorption by host from fungus. The hypothesis is developed that the fungus absorbs carbohydrates from the host and transforms them into reserve substances peculiar to itself, so maintaining a concentration gradient with respect to the host carbohydrate. The mycorrhizal system has the added advantage to the fungus that its reserve sugars are not readily re-available to the host. As polyols are abundant in many angiosperm parasites, the Physiology of polyols in general is reviewed with the conclusion that the role postulated for this class of compound in mycorrhizas may be applicable to host-parasite relations in general.
Article Mechanisms of plant survival and mortality during drought: why do some plants survive while others succumb to drought?
N. McDowell, W. T. Pockman, C. D. Allen, D. D. Breshers, N. Cobb, T. Kolb, J. Plaut, J. Sperry, A. West, D. G. Williams, E. A. Yepez
Summary Author for correspondence: Nate McDowell Tel: +1 505 6652909 Fax: +1 505 6653866 Email: mcdowell@lanl.gov
New Phytologist (2008) 178: 719 - 739 doi: 10.1111/j.1469-8137.2008.02436.x
Key words: climate, die-off, hydraulics, vegetation mortality, water relations
Severe droughts have been associated with regional-scale forest mortality worldwide. Climate change is expected to exacerbate regional mortality events; however, prediction remains difficult because the physiological mechanisms underlying drought survival and mortality are poorly understood. We developed a hydraulically based theory considering carbon balance and insect resistance that allowed development and examination of hypotheses regarding survival and mortality. Multiple mechanisms may cause mortality during drought. A common mechanism for plants with isohydric regulation of water status results from avoidance of drought-induced hydraulic failure via stomatal closure, resulting in carbon starvation and a cascade of downstream effects such as reduced resistance to biotic agents. Mortality by hydraulic failure per se may occur for isohydric seedlings or trees near their maximum height. Although anisohydric plants are relatively drought-tolerant, they are predisposed to hydraulic failure because they operate with narrower hydraulic safety margins during drought. Elevated temperatures should exacerbate carbon starvation and hydraulic failure. Biotic agents may amplify and be amplified by drought-induced plant stress. Wet multidecadal climate oscillations may increase plant susceptibility to drought-induced mortality by stimulating shifts in hydraulic architecture, effectively predisposing plants to water stress. Climate warming and increased frequency of extreme events will probably cause increased regional mortality episodes. Isohydric and anisohydric water potential regulation may partition species between survival and mortality, and, as such, incorporating this hydraulic framework may be effective for modeling plant survival and mortality under future climate conditions.
Article Stomata and hydathodes in Campanula rotundifolia L., and their relation to environment
M. W. Rea
New Phytologist (1921) 20: 56 - 72 doi: 10.1111/j.1469-8137.1921.tb05772.x
Many authors have commented on the varying number of stomata observed either on the leaves of related plants, or on the leaves of plants belonging to widely differing families. Very little work so far has been done, by using the same species grown under different conditions, to demonstrate the possibility that the number of stomata per unit area may vary according to the leaf surface and the position of the leaf on the shoot. In this connection Professor R. H. Yapp found in Spiraea Ulmaria L. (= Ulmaria palustris Moench.) a range from about 300 to nearly 1300 stomata per sq. mm. on the under surface (there were practically no stomata on the upper surface) for the lower and upper leaves respectively of the same shoot (7, p. 827). He states: "It may be that Spiraea Ulmaria is exceptional in the latter respect, but it would be worth while comparing the successive leaves of a number of other plants, for if the phenomenon is at all general, the numbers already published for a large number of species might need considerable revision."
Letter Physiological mechanisms of drought-induced tree mortality are far from being resolved
A. Sala, F. Piper, G. Hoch
Summary Author for correspondence: Anna Sala Tel: +406 243 6009 Email: sala@mso.umt.edu
New Phytologist (2010) 186: 274 - 281 doi: 10.1111/j.1469-8137.2009.03167.x
Key words: carbon pools, carbon starvation, drought, hydraulic constraints, phloem transport, reserves, tree mortality
The recent worldwide increase of drought-induced tree mortality exacerbated by climate change (see review by Allen et al., 2009 and references therein) has triggered strong interest in revisiting the exact mechanisms leading to mortality (McDowell et al., 2008). In addition to biotic factors such as pathogens and insects, which amplify the negative effects of drought or are amplified by elevated temperatures and drought (Desprez-Loustau et al., 2006; Rouault et al., 2006), two physiological mechanisms have been advanced in the literature and recently formalized by McDowell et al. (2008) within a hydraulic framework: hydraulic failure and carbon (C) starvation. Hydraulic failure occurs when drought intensity is sufficient to push a plant past its threshold for irreversible desiccation. The C starvation hypothesis has been invoked in the literature for decades (Parker & Patton, 1975) and predicts that reduced C assimilation via photosynthesis as a result of drought-induced stomatal closure – particularly in isohydric species that close stomata to maintain high (i.e. less negative) xylem water potentials (McDowell et al., 2008) – leads to an imbalance between C availability and C loss as a result of metabolic demands (e.g. growth and maintenance). Over time, if drought persists, such negative C balance can lead to an exhaustion of C reserves and, ultimately, to C starvation and death.
Article The symptoms of calcium deficiency in plants
E. W. Simon
Summary New Phytologist (1978) 80: 1 - 15 doi: 10.1111/j.1469-8137.1978.tb02259.x
As the symptoms of calcium deficiency develop in plants, there is often a stage in which the tissues are water-soaked and one involving cell breakdown with loss of turgor (as in internal breakdown of apples). Eventually the tissue may become desiccated yielding a dry, more or less extensive area of necrosis. Two mechanisms are proposed. There is evidence that calcium deficiency renders membranes permeable which would account for a loss of turgor and permit cell fluids to invade intercellular spaces. An alternative situation may develop in soft, succulent fruits, the cells of which burst under hypotonic conditions in vitro. It is suggested that exogenous water may enter a fruit from the atmosphere or (in apple) through the phloem. Such exogenous water in the intercellular spaces of the fruit may cause cells to swell, so cracking the fruit or it may result in a bursting of the cells. A plea is made for further light microscope studies of the development of symptoms of calcium deficiency.
Article Stelar evolution in vascular plants
B. F. Slade
Summary New Phytologist (1971) 70: 879 - 884 doi: 10.1111/j.1469-8137.1971.tb02588.x
Recently Namboodiri and Beck (1968c) and Beck (1970) in proposing a new hypothesis of stelar evolution in the gymnosperms failed to mention its possible application to angiosperms. This paper, by showing the close similarity of the primary vasculature of gymnosperms with that of the ‘parastichous type’ (Philipson and Balfour, 1963) in dicotyledons, shows that the hypothesis applies equally to both groups. Brief reference is made to other instances of stelar structure where application of the leaf-gap theory (Jeffrey, 1902, 1917) has failed. Here Namboodiri and Beck's new concept, that parenchymatous areas may arise having no association with leaf gaps, is most helpful.
Article The ‘xerophytic’ character of the Gymnosperms. Is it an ‘ecological’ adaptation?
M. C. Stopes
New Phytologist (1907) 6: 46 - 50 doi: 10.1111/j.1469-8137.1907.tb06042.x
That the living Coniferales, almost without exception, are xerophytic in their structure, is a statement of morphological and anatomical facts which are so well known as to require no illustration. Nevertheless, the distribution of the group at the present day, though wide, is in the main coincident with areas where the rainfall is plentiful, or at least sufficient to allow less protected plants to flourish. Frequently the marked protection of the gymnosperms seems out of place and superfluous, as it appears in the lives of many species of Abies, the large American forest trees, and in the various species commonly found growing in a mixed deciduous forest.
Article The problems of ecology
A. G. Tansley
New Phytologist (1904) 3: 191 - 200 doi: 10.1111/j.1469-8137.1904.tb07347.x
Ecology may now be considered almost a fashionable study, but there are not wanting botanists who tacitly distrust, even if they do not openly contemn, a good deal of the work which is done under its name. This hostile attitude is not always wholly to be wondered at, for the subject has its own difficulties and dangers, and these are sometimes rather distressingly patent in the papers of some of its votaries; on the other band the hostility alluded to is not seldom due to misapprehension, and it therefore appears useful to consider the subject from a general point of view in the hope of pointing out some of its dangers and of clearing up some of the misapprehension.
Article Xerophytic adaptations of bryophytes in relation to habitat
W. Watson
Introduction Part 1: New Phytologist (1914) 13: 149 - 169 doi: 10.1111/j.1469-8137.1914.tb05747.x
Part 2:
New Phytologist (1914) 13: 181 - 190 doi: 10.1111/j.1469-8137.1914.tb05749.x
Some years ago, when examining the bryophytes of the woodlands of Somersetshire (22), I was desirous of obtaining information on the characters which enable some species to live in dry situations, whilst others could only exist when provided with a large amount of shade or moisture. My search for information of this nature was only partially successful, as I could find no book or papers definitely dealing with it, but only scattered references to the subject in the works of Kerner (11), Goebel (7), Campbell (3), Haberlandt (9), Dixon (6), Warnstorf (19.21), Cavers (4, 5), Braithwaite (2), and others. Most of the required information had therefore to be gained from first-hand evidence by the study of the plants in the field and laboratory, and this paper is largely the result of such work, carried on for several years. A recent paper by Grebe (8) on the methods by which mosses protect themselves against drought, and an earlier series of articles by Wheldon (25), in which the xerophy tic characters of some mosses were clearly shown and explained are of great value; these have been very useful to me in my later investigations, and extensively used in the arrangement of the matter for the present paper, which however deals with the liverworts as well as the mosses.
Article The effect of wind on plant growth and soil moisture relations: a reply to the re-assessment by Humphries and Roberts
F. H. Whitehead
New Phytologist (1965) 64: 319 - 322 doi: 10.1111/j.1469-8137.1965.tb05401.x
Humphries and Roberts (1965) have put forward an interesting re-assessment of our papers on the effect of wind on plant growth and soil moisture relations given in the New Phytologist in 1962 and 1963. They believe that the data presented can be accounted for in terms of a restricted development of roots. The essence of this reassessment lies in the supposition that under experimental conditions of culture of plants at fractions of field capacity the soil was wetted in a restricted region only and that the remainder of the soil remained dry. Unfortunately, it was, perhaps, not made clear in the original papers that precautions were taken to avoid this situation. It seems that due to this omission they have made the assumption that the moisture content of the soil was maintained by surface addition of water. This was not the case since necessary amounts of water were added by means of a veterinary hypodermic syringe. The needle was plunged into the beakers in such a way that small amounts of water were added at different depths, etc., resulting in a much less uneven distribution than that produced by surface watering. It is not claimed that this led to a completely even distribution nor that the fractions of field capacity were maintained exactly in all parts of the soil. That it avoided any great reduction of the volume of soil available for root growth is clear from the fact that in all cases where plants were grown at less than field capacity there was proportionately less decrease in dry weight of root than that of shoot (see Whitehead, 1963a, Fig. 4).
Article Effect of light intensity during growth on leaf anatomy and subsequent light-saturated photosynthesis among contrasting Lolium genotypes D. Wilson, J. P. Cooper
Summary New Phytologist (1969) 68: 1125 - 1135 doi: 10.1111/j.1469-8137.1969.tb06512.x
The effect of light intensity during leaf formation on subsequent light-saturated photosynthesis and its relation to mesophyll and stomatal characteristics, was examined among ten contrasting Lolium genotypes. Photosynthetic activity was recorded at three CO2 concentrations. At approximately 300 ppm CO2 and above, plants of the same mesophyll cell size grown in strong light (0.130 cal/cm2 /min) of radiation in the spectral region 400–720 mΟ. (1800 ft-candles) had faster rates of photosynthesis than those grown in relatively weak light (0.021 or 0.056 cal/cm2 / min). At the lowest CO2 concentration there was no effect on photosynthesis of the light intensity at which the plants were grown. The effect of light intensity was not associated with any change in mesophyll structure, but plants grown in weaker light (0.056 cal/cm2 /min) had much smaller stomata than those grown in stronger light (0.130 cal/cm2 /min). A slight increase in stomatal frequency at the low compared with the high light intensity did not compensate for the reduced stomatal length in terms of total pore space. Differences in apparent photosynthesis in any one light intensity, and between plants from all light intensities at the lowest CO2 concentration, were usually correlated negatively with mesophyll cell size. Effects of the light intensity at which plants were grown on subsequent photosynthesis could be explained in terms of changes in stomatal size.
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