I read this book the same weekend that the Packers took on the Rams, and the experience of the latter event, obviously, colored my judgment. Although I abhor anything that smacks of being a handbook (like, \"How to Earn a Merit Badge in Neurosurgery\") because too many volumes in biomedical science already evince a boyscout-like approach, I must confess that parts of this volume are fast, scholarly, and significant, with certain reservations. I like parts of this well-illustrated book because Dr. Sj6strand, without so stating, develops certain subjects on technique in relation to the acquisition of judgment and sophistication. And this is important! So, given that the author (like all of us) is somewhat deficient in some areas, and biased in others, the book is still valuable if the uninitiated reader swallows it in a general fashion, realizing full well that what will be required from the reader is a modulation to fit his vision, propreception, adaptation and response, and the kind of problem he is undertaking. A major deficiency of this book is revealed by comparison of its use of physics and of chemistry to provide understanding and background for the application of high resolution electron microscopy to problems in biology. Since the volume is keyed to high resolution electron microscopy, which is a sophisticated form of structural analysis, but really morphology in a modern guise, the physical and mechanical background of The instrument and its ancillary tools are simply and well presented. The potential use of chemical or cytochemical information as it relates to biological fine structure , however, is quite deficient. I wonder when even sophisticated morphol-ogists will consider fixation a reaction and not a technique; only then will the fundamentals become self-evident and predictable and this sine qua flon will become less mystical. Staining reactions (the most inadequate chapter) ought to be something more than a technique to selectively enhance contrast of morphological elements; it ought to give the structural addresses of some of the chemical residents of cell components. Is it pertinent that auto-radiography gets singled out for more complete coverage than other significant aspects of cytochemistry by a high resolution microscopist, when it has a built-in minimal error of 1,000 A in standard practice? I don't mean to blind-side (in strict football terminology) Dr. Sj6strand's efforts for what is \"routinely used in our laboratory\"; what is done is usually well done. It's just that …

Methods in Enzymology.

Stressful environments such as salinity, drought, and high temperature (heat) cause alterations in a wide range of physiological, biochemical, and molecular processes in plants. Photosynthesis, the most fundamental and intricate physiological process in all green plants, is also severely affected in all its phases by such stresses. Since the mechanism of photosynthesis involves various components, including photosynthetic pigments and photosystems, the electron transport system, and CO2 reduction pathways, any damage at any level caused by a stress may reduce the overall photosynthetic capacity of a green plant. Details of the stress-induced damage and adverse effects on different types of pigments, photosystems, components of electron transport system, alterations in the activities of enzymes involved in the mechanism of photosynthesis, and changes in various gas exchange characteristics, particularly of agricultural plants, are considered in this review. In addition, we discussed also progress made during the last two decades in producing transgenic lines of different C3 crops with enhanced photosynthetic performance, which was reached by either the overexpression of C3 enzymes or transcription factors or the incorporation of genes encoding C4 enzymes into C3 plants. We also discussed critically a current, worldwide effort to identify signaling components, such as transcription factors and protein kinases, particularly mitogen-activated protein kinases (MAPKs) involved in stress adaptation in agricultural plants.

Photosynthesis under stressful environments: An overview

Positive ions that are available in soils absorb on grain surfaces. The total sum of cations that can be absorbed bij a soil/sediment at a certain PH is defined by the cation-exchange capacity (CEC, in meq g-1: mol equivalents per gram). The uptake of cations is an important parameter in agriculture and the larger the CEC, the more cations can be absorbed to the soil. The CEC depends highly on the pH of soil and sediments, where the CEC decreases with decreasing PH (increasing acidity). The exchange of ions on sediments occurs commonly fast on geological time scales, but the kinetics of adsorption in natural environments is still poorly understood. The strength of the bonding between the cations and the sediments varies from weak Van der Waals bondings (physical adsorption) to strong chemical bonds. The CEC is widely used for agricultural assessment because it is a measure of general soil fertility as well as an indicator of structural stability because CED is capabel of enhancing development of shrinkage cracks. The list below shows the CEC for different types of minerals. The data indicate that the CEC can vary over 2 orders of magnitude for various types of , minerals and can vary one order of magnitude within one soil type. Cation exchange capacity for different types of sediment (Eisma, 1992; Locher and de Bakker, 1990):

Cation exchange capacity.

Zinc in Soils and Crop Nutrition

統計年鑑 = Statistical yearbook

This study aims to explain the effects of silicon (Si) foliar application on gas exchange characteristics, photosynthetic pigments, membrane stability and leaf relative water content of different wheat cultivars in the field under drought stress conditions. The experiment was arranged as a split-split plot based on randomized complete block design with three replications. Irrigation regime (100%, 60%, and 40% F.C.), silicon (control and Si application) and wheat cultivars (Shiraz, Marvdasht, Chamran, and Sirvan) were considered as main, sub and sub-sub plots, respectively. This study was carried out at the Research Farm of the Collage of Agriculture, Shiraz University, Iran, during 2012–2013 growing season. The results showed that foliar application of silicon increased the leaf relative water content, photosynthesis pigments (chlorophyll a, b and total chl and carotenoids), chlorophyll stability index (CSI) and membrane stability index (MSI) in all wheat cultivars, especially in Sirvan and Chamra...

Effect of silicon on photosynthetic gas exchange, photosynthetic pigments, cell membrane stability and relative water content of different wheat cultivars under drought stress conditions

In most rainfed production areas in Iran, where wheat fallow is common, crop yield and resource sustainability could be improved by changing to more diverse crop rotation. It seems necessary to identify crop cultivars suitable for such diversification. This study was aimed to determine responses of two common bean (Phaseolus vulgaris L.) cultivars with different growth habits (Sayyad as an indeterminate and D81083 as a determinate cultivar) to water stress conditions. The study was conducted in controlled conditions (the greenhouse of Department of Crop Production and Plant Breeding, College of Agriculture Shiraz University, Shiraz, Iran) during 2008 growing season. There were four water stress levels (100, 75, 50 and 25% of field capacity by weight). The results showed that plant height, number of leaves, leaf area, number of pods, pod dry weight and total dry weight of both cultivars responded significantly to water stress conditions. Water stress also reduced stem height and reduced leaf area. Furthermore, it reduced pod dry weight in both cultivars and in 50 and 25% water stress levels, all plant pods of both cultivars were aborted. Common bean cultivar with determinate growth habit (D81083) appeared to have potential as a dryland rotation crop for arid areas with dryland farming. Further field research might shed more light on sensitivity of bean cultivars to water stress levels with the aim of crop diversification for dryland areas in Iran, where adequate moisture supply is limiting.

Water stress effects on two common bean cultivars with contrasting growth habits.

Physiological and antioxidant responses of winter wheat cultivars to strigolactone and salicylic acid in drought

A pot experiment was conducted in a greenhouse on a calcareous soil (fine, mixed, mesic, Fluventic Haploxerepts) to study the interaction of zinc (Zn) and boron (B) on the growth and nutrient concentration of corn (Zea mays L.). Treatments consisted of a factorial arrangement of seven levels of B (0, 2.5, 5, 10, 20, 40, and 80 mg kg− 1as boric acid), two sources of Zn [zinc sulfate (ZnSO4 · 7H2O) and zinc oxide (ZnO)], and three levels of Zn (0, 5, and 10 mg kg− 1) in a completely randomized design with three replications. Plants were grown for 70 d in 1.6 L plastic containers. Applied Zn significantly increased plant height and dry matter yield (DMY) of corn. Source of Zn did not significantly affect growth or nutrient concentration. High levels of B decreased plant height and DMY. There was a significant B × Zn interaction on plant growth and tissue nutrient concentration which were rate dependent. In general, the effect of B × Zn interaction was antagonistic on nutrient concentration and syner...

Effect of zinc x boron interaction on plant growth and tissue nutrient concentration of corn

Seed priming is a method to improve germination and seedling establishment under stress conditions. The effect of seed priming in chemical solutions such as urea and KNO3, on protein and proline content, germination, and seedling growth responses of four maize (Zea mays L.) hybrids under drought and salt stress conditions was studied in a controlled environment in 2010. Treatments included stress type and intensity at five levels: moderate drought (MD), severe drought (SD), moderate salt (MS), severe salt (SS), and control (C1, without stress), three seed priming types including water (C2, as control), KNO3, and urea (as chemical priming), and four maize hybrids including Maxima, SC704, Zola, and 307. The results showed that the highest germination percentage (Ger %), germination rate (GR), seedling length (SL), radical length (RL), and seedling to radical length ratio (S/R) were achieved in no stress treatments and most proline content in SD treatment. Urea priming led to more Ger%, GR, and SL compared to other primers and treatment under KNO3 priming resulted in higher RL compared to other primers. Chemical priming had no effect on S/R and proline content. Also, in terms of most traits, no difference was found among the four hybrids. Results showed that salt stress could affect GR and RL more than the drought stress. Drought stress affected germination percentage and S/R more than the salt stress. Both stresses decreased all measured parameters, except protein and proline content which were increased remarkably, and more under drought compared to salt stress. Based on proline content, hybrid 304 appeared to be more resistant to stress than other hybrids. Generally, KNO3 and urea alleviated effects of both stresses and led to increased germination and seedling growth as well as the root length. Therefore, priming could be recommended for enhancing maize growth responses under stressful conditions.

Yahya Emam

Papers

Effect of silicon on photosynthetic gas exchange, photosynthetic pigments, cell membrane stability and relative water content of different wheat cultivars under drought stress conditions

Water stress effects on two common bean cultivars with contrasting growth habits.

Physiological and antioxidant responses of winter wheat cultivars to strigolactone and salicylic acid in drought

Effect of zinc x boron interaction on plant growth and tissue nutrient concentration of corn

Chemical priming with urea and KNO3 enhances maize hybrids (Zea mays L.) seed viability under abiotic stress