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2. Brandt iH026a plant growth regulator

Creator:
Nonomura, A. M., Pedersen, A., Brummel, D. P., Loveless, L., Lauria, A., Haschemeyer, B., and McBride, M. S.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
zemědělství, regulátory růstu rostlin, dýchání, agriculture, plant growth regulators, respiration, glycoside, Govindjee, photosynthate, Z-scheme, 2, and 581
Language:
Multiple languages
Description:
iH026a is a formulation containing a biochemical class of plant growth regulator that modulates glycoconjugation through the plant lectin cycle. While lectins are common to vascular plants, we observed, consistent with reversible binding of sugars from lectins, enhancements of quantities and qualities of various features, including significant enrichment of Brix soluble sugars compared to controls in cherry, grape, and melon in trials conducted in Arizona and California, USA., A. M. Nonomura, A. Pedersen, D. P. Brummel, L. Loveless, A. Lauria, B. Haschemeyer, M. S. McBride, and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Comparative photosynthesis, growth, productivity, and nutrient use efficiency among tall- and short-stemmed rain-fed cassava cultivars

Creator:
El-Sharkawy, M. A. and de Tafur, S. M.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, agriculture, breeding, C3-C4, canopy, drought, ecophysiology, environment, gas exchange, leaf, Manihot, soils, tropics, and yield
Language:
Multiple languages
Description:
Field trials under rain-fed conditions at the International Center for Tropical Agriculture (CIAT) in Colombia were conducted to study the comparative leaf photosynthesis, growth, yield, and nutrient use efficiency in two groups of cassava cultivars representing tall (large leaf canopy and shoot biomass) and short (small leaf canopy and shoot biomass) plant types. Using the standard plant density (10,000 plants ha-1), tall cultivars produced higher shoot biomass, larger seasonal leaf area indices (LAIs) and greater final storage root yields than the short cultivars. At six months after planting, yields were similar in both plant types with the short ones tending to form and fill storage roots at a much earlier time in their growth stage. Root yield, shoot and total biomass in all cultivars were significantly correlated with seasonal average LAI. Short cultivars maintained lower than optimal LAI for yield. Seasonal PN, across cultivars, was 12% greater in short types, with maximum values obtained in Brazilian genotypes. This difference in PN was attributed to nonstomatal factors (i.e., anatomical/biochemical mesophyll characteristics). Compared with tall cultivars, short ones had 14 to 24 % greater nutrient use efficiency (NUE) in terms of storage root production. The lesser NUE in tall plants was attributed mainly to more total nutrient uptake than in short cultivars. It was concluded that short-stemmed cultivars are superior in producing dry matter in their storage roots per unit nutrient absorbed, making them advantageous for soil fertility conservation while their yields approach those in tall types. It was recommended that breeding programs should focus on selection for more efficient short- to medium-stemmed genotypes since resource-limited cassava farmers rarely apply agrochemicals nor recycle residual parts of the crop back to the soil. Such improved short types were expected to surpass tall types in yields when grown at higher than standard plant population densities (>10,000 plants ha-1) in order to maximize irradiance interception. Below a certain population density (<10,000 plants ha-1), tall cultivars should be planted. Findings were discussed in relation to cultivation and cropping systems strategies for water and nutrient conservation and use efficiencies under stressful environments as well as under predicted water deficits in the tropics caused by trends in global climate change. Cassava is expected to play a major role in food and biofuel production due to its high photosynthetic capacity and its ability to conserve water as compared to major cereal grain crops. The interdisciplinary/interinstitutions research reported here, including, an associated release of a drought-tolerant, short-stem cultivar that was eagerly accepted by cassava farmers, reflects well on the productivity of the CIAT international research in Cali, Colombia., and M. A. El-Sharkawy, S. M. de Tafur
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Global warming: causes and impacts on agroecosystems productivity and food security with emphasis on cassava comparative advantage in the tropics/subtropics

Creator:
El-Sharkawy, M. A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, zemědělství, klimatické změny, oxid uhličitý, zemědělské plodiny, lesy, skleníkové plyny, modelování a simulace, půda, teplota, globální oteplování, photosynthesis, agriculture, climate changes, carbon dioxide, agricultural crops, forests, greenhouse gases, modeling and simulation, soil, temperature, global warming, animal husbandry, cassava, tropics, subtropics, water stress, wild Manihot species, yield, 2, and 581
Language:
Multiple languages
Description:
Earth’s climate has experienced notable changes during the past 50-70 years when global surface temperature has risen by 0.8°C during the 20th century. This was a consequence of the rise in the concentration of biogenic gases (carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, and ozone) in the atmosphere that contribute, along with water vapor, to the so-called ‘greenhouse effect’. Most of the emissions of greenhouse gases have been, and still are, the product of human activities, namely, the excessive use of fossil energy, deforestations in the humid tropics with associated poor land use-management, and wide-scale degradation of soils under crop cultivation and animal/pasture ecosystems. General Circulation Models predict that atmospheric CO2 concentration will probably reach 700 μmol(CO2) mol-1. This can result in rise of Earth’s temperature from 1.5 to over 5°C by the end of this century. This may instigate 0.60-1.0 m rise in sea level, with impacts on coastal lowlands across continents. Crop modeling predicts significant changes in agricultural ecosystems. The mid- and high-latitude regions might reap the benefits of warming and CO2 fertilization effects via increasing total production and yield of C3 plants coupled with greater water-use efficiencies. The tropical/subtropical regions will probably suffer the worst impacts of global climate changes. These impacts include wide-scale socioeconomic changes, such as degradation and losses of natural resources, low agricultural production, and lower crop yields, increased risks of hunger, and above all waves of human migration and dislocation. Due to inherent cassava tolerance to heat, water stress, and poor soils, this crop is highly adaptable to warming climate. Such a trait should enhance its role in food security in the tropics and subtropics., M. A. El-Sharkawy., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Pioneering research on C4 leaf anatomical, physiological, and agronomic characteristics of tropical monocot and dicot plant species: Implications for crop water relations and productivity in comparison to C3 cropping systems

Creator:
El-Sharkawy, M. A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
agriculture, biochemistry, breeding, carbon assimilation, crops, drought, enzymes, gas exchange, photorespiration, photosynthesis, and water use efficiency
Language:
Multiple languages
Description:
The review is done to summarise the history of the discoveries of the many anatomical, agronomical, and physiological aspects of C4 photosynthesis (where the first chemical products of CO2 fixation in illuminated leaves are four-carbon dicarboxylic acids) and to document correctly the scientists at the University of Arizona and the University of California, Davis, who made these early discoveries. The findings were milestones in plant science that occurred shortly after the biochemical pathway of C3 photosynthesis in green algae (where the first chemical product is a three-carbon compound) was elucidated at the University of California, Berkeley, and earned a Nobel Prize in chemistry. These remarkable achievements were the result of ground-breaking pioneering research efforts carried out by many agronomists, plant physiologists and biochemists in several laboratories, particularly in the USA. Numerous reviews and books written in the past four decades on the history of C4 photosynthesis have focused on the biochemical aspects and give an unbalanced history of the multidisciplinary/multinstitutional nature of the achievements made by agronomists, who published much of their work in Crop Science. Most notable among the characteristics of the C4 species that differentiated them from the C3 ones are: (I) high optimum temperature and high irradiance saturation for maximum leaf photosynthetic rates; (II) apparent lack of CO2 release in a rapid stream of CO2-free air in illuminated leaves in varying temperatures and high irradiances; (III) a very low CO2 compensation point; (IV) lower mesophyll resistances to CO2 diffusion coupled with higher stomatal resistances, and, hence, higher instantaneous leaf water use efficiency; (V) the existence of the so-called "Kranz leaf anatomy" and the higher internal exposed mesophyll surface area per cell volume; and (VI) the ability to recycle respiratory CO2 by illuminated leaves.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public