scholarly journals Water stress-induced changes in morphology and anatomy of flag leaf of spring wheat

2014 ◽  
Vol 63 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Barbara Zagdańska ◽  
Janusz Kozdój
Keyword(s):  
Water Stress ◽  
Leaf Anatomy ◽  
Flag Leaf ◽  
Decisive Role ◽  
Mesophyll Cells ◽  
Flag Leaves ◽  
Leaf Area And Thickness ◽  
Total Cell Volume ◽  
Simultaneous Decrease ◽  
Induced Changes

Flag leaves of wheat (drought hardened and non-hardened) were examined by light microscopy to determine whether the differences in leaf anatomy could be related to the known differences in dehydration tolerance. Plants exposure to water stress during tissue differentiation of flag leaves resulted in an irreversible reduction of leaf area and thickness, increased frequencies of stomata and higher number of bulliform cells with simultaneous decrease in number of intermediate veins and an increase in the share of the cell walls in total cell volume. The smaller leaf thickness was due to a diminished number of mesophyll layers and a decreased size of mesophyll cells. Such altered leaf anatomy indicated development of leaf xerophily. It was found that the irreversible changes in anatomy of wheat flag leaves play a decisive role in acquiring drought tolerance during wheat acclimation to drought.

YIELD PERFORMANCE, CARBON ASSIMILATION AND SPECTRAL RESPONSE OF TRITICALE TO WATER STRESS

2016 ◽  
Vol 53 (1) ◽  
pp. 100-117 ◽  
Author(s):  
LAWRENCE MUNJONJI ◽  
KINGSLEY K. AYISI ◽  
BRAM VANDEWALLE ◽  
INOS DHAU ◽  
PASCAL BOECKX ◽  
...  
Keyword(s):  
Water Stress ◽  
Grain Yield ◽  
Carbon Content ◽  
Spectral Reflectance ◽  
Flag Leaf ◽  
Moisture Level ◽  
Yield Performance ◽  
Flag Leaves ◽  
Water Index ◽  
Spring Triticale

SUMMARYWater stress is arguably the most limiting factor affecting cereal productivity in the world and its effects are likely to increase due to climate change. It is therefore imperative to have a wide-ranging understanding of water stress effects on crop physiological processes so as to better manage, improve and adapt crops to future climates. A field study was carried out to investigate the influence of four moisture levels on the following: (1) flag leaf CO2 assimilation and flag leaf carbon content; (2) the utility of flag leaf spectral reflectance to monitor leaf water status and as an indicator of biomass and grain yield; and (3) biomass and grain yield performance of four spring triticale genotypes in a dry winter environment (steppe, arid climate). The experiment was carried out in a factorial arrangement of four moisture levels and four spring type triticale genotypes). Soil moisture level significantly influenced biomass accumulation, grain yield, CO2 assimilation, flag leaf carbon content and spectral reflectance. Grain yield levels ranged from 0.8 to 3.5 t ha−1 in 2013 and 1.8 to 4.9 t ha−1 in 2014. CO2 assimilation was significantly higher under well-watered (WW) conditions (9.92 µmol m−2 s−1 in 2013; 11.64 µmol m−2 s−1 in 2014) and decreased gradually with moisture level to 1.82 and 4.74 µmol m−2 s−1 under severe stress (SS) in 2013 and 2014, respectively. Flag leaf carbon content was significantly higher under water limited conditions compared to WW. Normalised Difference Vegetation Index (NDVI), Normalised Difference Water Index (NDWI) and Water Index (WI) were significant and positively correlated to biomass and grain yield. WI was particularly strongly correlated to biomass (0.72***) and grain yield (0.55***). However, no clear varietal effects were detected. This study revealed that carbon tends to accumulate in flag leaves under water stress and that flag leaf carbon content is influenced more by the export capacity of the flag leaves than on CO2 assimilation rate. WI was found to be superior index in monitoring water stress in triticale compared to NDVI and NDWI. Above all, spring triticale proved to be adaptable to steppe (dry) climate of Limpopo and that livestock farmers in the province can successfully grow triticale for silage under MS conditions.

scholarly journals Beyond genetics – The emerging role of epigenetics and its clinical aspects

2012 ◽  
Vol 153 (6) ◽  
pp. 214-221 ◽  
Author(s):  
Veronika Urbán S. ◽  
Elizabeta Benevolenskaya ◽  
Judit Kiss ◽  
Bernadett Sági ◽  
Beáta Hegyi ◽  
...  
Keyword(s):  
Decisive Role ◽  
Clinical Aspects ◽  
Dynamic Complexity ◽  
Spatial Changes ◽  
Future Drug ◽  
A Cell ◽  
Multiple Cell ◽  
Induced Changes ◽  
Cell Phenotypes ◽  
Diversity Of Life

Analysis of genomic sequences has clearly shown that the genomic differences among species do not explain the diversity of life. The genetic code itself serves as only a part of the dynamic complexity that results in the temporal and spatial changes in cell phenotypes during development. It has been concluded that the phenotype of a cell and of the organism as a whole is more influenced by environmentally-induced changes in gene activity than had been previously thought. The emerging field of epigenetics focuses on molecular marks on chromatin; called the epigenome, which serve as transmitters between the genome and the environment. These changes not only persist through multiple cell division cycles, but may also endure for multiple generations. Irregular alterations of the epigenome; called epimutations, may have a decisive role in the etiology of human pathologies such as malignancies and other complex human diseases. Epigenetics can provide the missing link between genetics, disease and the environment. Therefore, this field may have an increasing impact on future drug design and serve as a basis for new therapeutic/preventative approaches. Orv. Hetil., 2012, 153, 214–221.

Water-Stress-Induced Changes in Resin and Rubber Concentration and Distribution in Greenhouse-Grown Guayule

2006 ◽  
Vol 98 (3) ◽  
pp. 766-773 ◽  
Author(s):  
Maren E. Veatch-Blohm ◽  
Dennis T. Ray ◽  
William B. McCloskey
Keyword(s):  
Water Stress ◽  
Induced Changes

Effect of Dikegulac Sodium on Water Stress-induced Changes in Vigna sinensis (L.) Walp.

1989 ◽  
Vol 184 (3-4) ◽  
pp. 285-292
Author(s):  
Ajoy K. Biswas ◽  
Hasna Hena Begam ◽  
M.A. Choudhuri
Keyword(s):  
Water Stress ◽  
Vigna Sinensis ◽  
Induced Changes

Leaf Ultrastructure and δ13C Values of Three Seagrasses from the Great Barrier Reef

1976 ◽  
Vol 3 (1) ◽  
pp. 9 ◽  
Author(s):  
ME Doohan ◽  
EH Newcomb
Keyword(s):  
Great Barrier Reef ◽  
Leaf Anatomy ◽  
Co2 Assimilation ◽  
Land Plants ◽  
Vascular Bundles ◽  
Barrier Reef ◽  
Thalassia Hemprichii ◽  
Mesophyll Cells ◽  
Δ13c Values ◽  
Abundant Cytoplasm

Leaf anatomy, ultrastructure and 13C/12C ratios were studied in three species of seagrasses collected on the Great Barrier Reef: Cymodocea rotundata Ehrenb. & Hempr., C. serrulata (R. Br.) Aschers. & Magnus, and Thalassia hemprichii (Ehrenb.) Aschers. Although they belong to two different mono- cotyledonous families, the three species are quite similar in the characteristics studied. Cells of the epidermal layer of the leaves are extremely thick-walled and have abundant cytoplasm with large chloroplasts and numerous mitochondria. The chloroplast-microbody profile ratio is c. 4-5 : 1 and the mitochondrion-microbody ratio 10-15 : 1. The epidermal cells resemble transfer cells in having a pronounced development of ingrowths on the radial walls. The mesophyll cells have thin walls, a large central vacuole and a thin layer of cytoplasm with relatively few organelles. There is no specialization of mesophyll cells around the vascular bundles. The δ13C values for the three sea- grasses range from -6.90, to - 12.40, and thus are characteristic of C4 land plants, although the seagrasses do not conform to the C4 syndrome in leaf anatomy or ultrastructure. It is not possible to place the seagrasses in either the C3, C4 or crassulacean acid metabolism category of land plants, but whether they constitute yet a fourth group with respect to characteristics related to CO2 assimilation is not clear.

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