1. Plant Nutrients. 2. The Soil as a Plant Nutrient Medium. 3. Nutrient Uptake and Assimilation. 4. Plant Water Relationships. 5. Plant Growth and Crop Production. 6. Fertilizer Application. 7. Nitrogen. 8. Sulphur. 9. Phosphorus. 10. Potassium. 11. Calcium. 12. Magnesium. 13. Iron. 14. Manganese. 15. Zinc. 16. Copper. 17. Molybdenum. 18. Boron. 19. Further Elements of Importance. 20. Elements with More Toxic Effects. General Readings. References. Index.

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Principles of plant nutrition

http://www.uniroma2.it/didattica/piante_medicinali/deposito/Carotenoidi.pdf

Carotenoids and human health

Summary Here, the coevolution of mycorrhizal fungi and roots is assessed in the light of evidence now available, from palaeobotanical and morphological studies and the analysis of DNA-based phylogenies. The first bryophyte-like land plants, in the early Devonian (400 million years ago), had endophytic associations resembling vesicular‐ arbuscular mycorrhizas (VAM) even before roots evolved. Mycorrhizal evolution would have progressed from endophytic hyphae towards balanced associations where partners were interdependent due to the exchange of limiting energy and nutrient resources. Most mycorrhizas are mutualistic, but in some cases the trend for increasing plant control of fungi culminates in the exploitative mycorrhizas of achlorophyllous, mycoheterotrophic plants. Ectomycorrhizal, ericoid and orchid mycorrhizas, as well as nonmycorrhizal roots, evolved during the period of rapid angiosperm radiation in the Cretaceous. It is hypothesised that roots gradually evolved from rhizomes to provide more suitable habitats for mycorrhizal fungi and provide plants with complex branching and leaves with water and nutrients. Selection pressures have caused the morphological divergence of roots with different types of mycorrizas. Root cortex thickness and exodermis suberization are greatest in obligately mycorrhizal plants, while nonmycorrhizal plants tend to have fine roots, with more roots hairs and relatively advanced chemical defences. Major coevolutionary trends and the relative success of plants with different root types are discussed.

Coevolution of roots and mycorrhizas of land plants

Methods for measuring plant cytoplasmic calcium using microelectrodes or microinjected fluorescent dyes are associated with extensive technical problems, so measurements have been limited to single or small groups of cells in tissue strips or protoplasts. Aequorin is a calcium-sensitive luminescent protein from the coelenterate Aequorea victoria (A. forskalea) which is formed from apoaequorin, a polypeptide of relative molecular mass approximately 22,000, and coelenterazine, a hydrophobic luminophore. Microinjected aequorin has been widely used for intracellular calcium measurement in animal cells, but its use in plants has been limited to exceptionally large cells. We show here that aequorin can be reconstituted in transformed plants and that it reports calcium changes induced by touch, cold-shock and fungal elicitors. Reconstituted aequorin is cytoplasmic and nonperturbing; measurements can be made on whole plants and a calcium indicator can be constituted in every viable cell. Now that apoaequorin can be targeted to specific organelles, cells and tissues, with the range of coelenterazines with differing calcium sensitivities and properties available, this new method could be valuable for determining the role of calcium in intracellular signalling processes in plants.

Transgenic plant aequorin reports the effects of touch and cold-shock and elicitors on cytoplasmic calcium.

A comprehensive appraisal of the mycorrhizal literature provides data for 336 plant families representing 99% of flowering plants, with regard to mycorrhizas and other nutritional adaptations. In total, arbuscular (AM), orchid, ectomycorrhizas (EM) and ericoid mycorrhizas and nonmycorrhizal (NM) roots occur in 74%, 9%, 2%, 1% and 6% of Angiosperm species respectively. Many families of NM plants have alternative nutritional strategies such as parasitism, carnivory, or cluster roots. The remaining angiosperms (8%) belong to families reported to have both AM and NM species. These are designated as NM-AM families here and tend to occur in habitats considered non-conducive to mycorrhizal fungi, such as epiphytic, aquatic, extremely cold, dry, disturbed, or saline habitats. Estimated numbers of species in each category of mycorrhizas is presented with lists of NM and EM families. Evolutionary trends are also summarised by providing data on all clades and orders of flowering and non-flowering vascular plants on a global scale. A case study of Western Australian plants revealed that plants with specialised nutritional modes such as carnivory, cluster roots, or EM were much more diverse in this ancient landscape with infertile soils than elsewhere. Detailed information on the mycorrhizal diversity of plants presented here is linked to a website (mycorrhizas.info) to allow data to remain current. Over a century of research effort has resulted in data on mycorrhizal associations of >10,000 plant species that are of great value, but also somewhat of a liability due to conflicting information about some families and genera. It is likely that these conflicts result in part from misdiagnosis of mycorrhizal associations resulting from a lack of standardisation in criteria used to define them. Families that contain both NM and AM species provide a second major source of inconsistency, but even when these are excluded there is a ∼10% apparent error rate in published lists of mycorrhizal plants. Arbuscules are linked to AM misdiagnosis since they are used less often than vesicles to recognise AM associations in roots and apparently occur sporadically in NM plants. Key issues with the diagnosis of mycorrhizal plants are discussed using the Cyperaceae as a case study. Detailed protocols designed to consistently distinguish AM from endophytic Glomeromycotan Fungus Colonisation (GFC) are provided. This review aims to stimulate debate and provide advice to researchers delving into root biology.

Mycorrhizal associations and other means of nutrition of vascular plants: understanding the global diversity of host plants by resolving conflicting information and developing reliable means of diagnosis

. It is suggested that increased levels of free cytosolic calcium ([Ca2+]cyt) may serve as the primary physiological transducer of chilling injury in plants. Numerous similarities between the effects of [Ca2+]cyt-raising treatments on plants and the effects of chilling temperatures on chilling-sensitive (CS) plants are noted. It is proposed that chilling temperatures may lead to increases in [Ca2+]cyt in CS plant cells by reducing the rate at which they exclude Ca2+ from their cytosol and that rapid cooling (coldshock) may cause rapid increases in [Ca2+]cyt due to the activation of voltage-dependent cation channels. Chill-induced increases in [Ca2+]cyt in the cells of CS plants may reflect either an inherent inability of such plants to maintain homeostatic levels of Ca2+ at low temperatures or a stress-induced reaction which has evolved to enable such cells to cope more effectively with the short-term hardships imposed by cold. Previous proposals concerning the physiological transduction of chilling injury are also discussed. It is argued that there is little evidence to suggest that the immediate effects of low temperatures on CS cells include either decreases in ATP levels, general increases in the passive permeability of membranes, or increased rates of fermentation.

An heuristic hypothesis of chilling injury in plants: a role for calcium as the primary physiological transducer of injury

It's likely that as long as humans have made note of plant function, the legume family has been of interest. Not only do legumes provide fodder for animals and nutrition-rich seeds for humans, but ancient cultures were aware of the ability of many legumes to improve the soil, a result of symbiotic

The Hot and the Classic

. The different effects which fast versus slow cooling have on such fundamental plant processes as ion transport, protoplasmic streaming, phloem translocation, growth, cell motility, water absorption and membrane potential are reviewed. When plant cells are rapidly cooled to non-injurious temperatures, many of the physiological ramifications of rapid-cooling stimulation are only transiently observed. It is proposed that these transient rapid-cooling-induced responses, sometimes elicited by temperature drops of only a few degrees centigrade, are manifestations of temperature sensing. The hypothesis is advanced that graded potentials, produced in response to rapidly falling temperature, are associated with graded increases in cytosolic free calcium. These transient increases in cytosolic free calcium give rise to many of the physiological effects elicited by rapid cooling. Other effects, however, such as those associated with alterations in membrane composition, gene expression and post-translational modifications of proteins, may persist longer. The questions of the possible physiological advantage of temperature sensing, and its implications for the study of chilling injury, are discussed.

Temperature sensing by plants: a review and hypothesis

Since its discovery in the early 1960s, abscisic acid (ABA) has received considerable attention as an important phytohormone, and more recently, as a candidate medicinal in humans. In plants it has been shown to regulate important physiological processes such as response to drought stress, and dormancy. The discovery of ABA synthesis in animal cells has generated interest in the possible parallels between its role in plant and animal systems. The importance of this molecule has prompted the development of several methods for the chemical synthesis of ABA, which differ significantly from the biosynthesis of ABA in plants through the mevalonic acid pathway. ABA recognition in plants has been shown to occur at both the intra- and extracellularly but little is known about the perception of ABA by animal cells. A few ABA molecular targets have been identified in vitro (e.g., calcium signaling, G protein-coupled receptors) in both plant and animal systems. A unique finding in mammalian systems, however, is that the peroxisome proliferator-activated receptor, PPAR γ, is upregulated by ABA in both in vitro and in vivo studies. Comparison of the human PPAR γ gene network with Arabidopsis ABA-related genes reveal important orthologs between these groups. Also, ABA can ameliorate the symptoms of type II diabetes, targeting PPAR γ in a similar manner as the thiazolidinediones class of anti-diabetic drugs. The use of ABA in the treatment of type II diabetes, offers encouragement for further studies concerning the biomedical applications of ABA.

Peter V. Minorsky

Papers

An heuristic hypothesis of chilling injury in plants: a role for calcium as the primary physiological transducer of injury

The Hot and the Classic

Temperature sensing by plants: a review and hypothesis

Mechanisms of action and medicinal applications of abscisic Acid.

Achieving the in Silico Plant. Systems Biology and the Future of Plant Biological Research