The Fractionation of 2H and 18O in Leaf Water of Barley

1991 ◽  
Vol 18 (4) ◽  
pp. 411 ◽  
Author(s):  
CD Walker ◽  
RCM Lance
Keyword(s):  
Flag Leaf ◽  
Leaf Water ◽  
Plant Parts ◽  
Barley Cultivars ◽  
Isotopic Compositions ◽  
Water Composition ◽  
Use Efficiency ◽  
Stem Water ◽  
Glasshouse Experiment ◽  
Almost All

Small changes in the natural abundance of hydrogen and oxygen isotopes in water occur as a result of transpiration. We considered whether these may be sufficient to study the differences in water relations of barley cultivars having different water-use efficiency (W). A range of cultivars of varying W were grown in the glasshouse and in the field in breeders' plots. Foliage water samples were taken from a specific leaf stage over the course of a day. Certain field-grown cultivars had consistently higher 2H and 18O compositions in foliage water than others at almost all sampling times, resulting in a consistent ranking of the cultivars. Some evidence of a consistent ranking of isotopic compositions was also present in the glasshouse experiment. Concurrent variations in 2H and 18O compositions of the stem and leaf water reflect the conditions under which transpiration is occurring. The composition of stem water remains steady over the course of such experiments. The slope of the line connecting the isotopic compositions of the stem water and leaf water varied with changes in leaf water composition. This variation in slope was more pronounced under the more humid conditions of the glasshouse experiment, as is predicted from theory. The 2H and 18O compositions of water in the other plant parts, atmosphere and soil were also examined and porometry measurements were made. These indicated that daily variations in the contributions of soil and leaf water to the atmosphere occurred. This involves a maximum in the proportion of soil evaporation in the middle of the day, and a converse maximum in flag leaf evaporation early and late in the solar day.

Simultaneous recording of diurnal changes in leaf turgor pressure and stem water status of bread wheat reveal variation in hydraulic mechanisms in response to drought

2015 ◽  
Vol 42 (10) ◽  
pp. 1001 ◽  
Author(s):  
Helen Bramley ◽  
Rebecca Bitter ◽  
Gertraud Zimmermann ◽  
Ulrich Zimmermann
Keyword(s):  
Water Status ◽  
Flag Leaf ◽  
Turgor Pressure ◽  
Crop Productivity ◽  
Simultaneous Recording ◽  
Diurnal Changes ◽  
Use Efficiency ◽  
Stem Water ◽  
The Impact ◽  
Kinetics Of

Information about water relations within crop canopies is needed to improve our understanding of canopy resource distribution and crop productivity. In this study, we examined the dehydration/rehydration kinetics of different organs of wheat plants using ZIM-probes that continuously monitor water status non-destructively. ZIM-probes were clamped to the flag leaf and penultimate leaf of the same stem to monitor changes in turgor pressure, and a novel stem probe was clamped to the peduncle (just below the spike of the same stem) to monitor changes in stem water status. All organs behaved similarly under well-watered conditions, dehydrating and recovering at the same times of day. When water was withheld, the behaviour diverged, with the leaves showing gradual dehydration and incomplete recovery in leaf turgor pressure during the night, but the stem was affected to a lesser extent. Penultimate leaves were the most severely affected, reaching turgor loss point before the flag leaf. Upon rewatering, turgor pressure recovered but the output patch-pressure of the probes (Pp) oscillated at ~30 min periods in all organs of most plants (n = 4). Oscillations in Pp were attributed to oscillations in stomatal opening and appear to only occur above a threshold light intensity. The mechanisms identified in this study will be beneficial for crop productivity because the flag leaf is the source of most photoassimilates in developing grains, so the plant’s ability to maintain flag leaf hydration at the expense of older leaves should moderate the impact of drought on yield. Stomatal oscillations could increase water use efficiency as the plant attempts to rehydrate after drought.

Agronomic and Physiological Responses of Soybean and Sorghum Crops to Water Deficits. IV. Photosynthesis, Transpiration and Water Use Efficiency in Leaves

1978 ◽  
Vol 5 (2) ◽  
pp. 195 ◽  
Author(s):  
HM Rawson ◽  
NC Turner ◽  
JE Begg
Keyword(s):  
Water Use Efficiency ◽  
Water Potential ◽  
Water Use ◽  
Leaf Water Potential ◽  
Flag Leaf ◽  
Grain Filling ◽  
Leaf Water ◽  
Water Deficits ◽  
Use Efficiency ◽  
Soybean Leaves

Detailed diurnal measurements of photosynthesis, transpiration and water use efficiency of leaves of sorghum and soybean were made during the reproductive growth of field plants. Photosynthesis was measured mainly by infrared gas techniques. The indication in well watered plants was that diurnal net carbon fixation per unit area of sorghum leaves was some 2.3 times greater than that of comparably illuminated soybean leaves while concurrent transpiration losses were less. Simple carbon budgets for the two crops over 24 h suggested that the assimilation by a leaf area equivalent to that of the flag leaf was required solely to sustain respiration by the sorghum head during mid- grain filling, while approximately 5 cm� of leaf was required to sustain respiration of each soybean pod. The comparisons made on a diurnal basis between plants of soybean exposed to different water deficits during grain filling demonstrated the increasing importance of early morning and late afternoon photosynthesis as water became less available. They also showed the rapidity with which plants can recover from stress once water is supplied. It is calculated that, for continuously clear conditions, as daily minimum leaf water potential fell from - 1 .5 to - 2.5 MPa, the integrated daily assimilation by leaves was reduced by about 9 % for every 0.1 MPa change; soybean leaves were not measured at leaf water potentials much below - 2.6 MPa. A ratio between gas phase and residual resistances remained relatively stable over the range of leaf water potential measured. However, the water use efficiency of single leaves was reduced with increasing soil water deficits because of changes in leaf temperature and leaf-to-air vapour pressure differences.

scholarly journals Hops (Humulus lupulus L.) as a Novel Multipurpose Crop for the Mediterranean Region of Europe: Challenges and Opportunities of Their Cultivation

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 484
Author(s):  
Francesco Rossini ◽  
Giuseppe Virga ◽  
Paolo Loreti ◽  
Nicolò Iacuzzi ◽  
Roberto Ruggeri ◽  
...  
Keyword(s):  
Humulus Lupulus ◽  
Specific Reference ◽  
Research Activity ◽  
Plant Parts ◽  
Craft Beer ◽  
Recent Success ◽  
Natural Medicine ◽  
Humulus Lupulus L ◽  
Challenges And Opportunities ◽  
Almost All

The common hop (Humulus lupulus L.) is a dioecious perennial climbing plant, mainly known for the use of its female inflorescences (cones or, simply, “hops”) in the brewing industry. However, the very first interest towards hops was due to its medicinal properties. Actually, the variety of compounds present in almost all plant parts were (and still are) used to treat or prevent several ailments and metabolic disorders, from insomnia to menopausal symptoms as well as obesity and even cancer. Although hops are predominantly grown for hopping beer, the increasing interest in natural medicine is widening new interesting perspectives for this crop. Moreover, the recent success of the craft beer sector all over the world, made the cultivated hop come out from its traditional growing areas. Particularly, in Europe this resulted in a movement towards southern countries such as Italy, which added itself to the already existing hop industry in Portugal and Spain. In these relatively new environments, a complete knowledge and expertise of hop growing practices is lacking. Overall, while many studies were conducted globally on phytochemistry, bioactivity, and the genetics of hops, results from public research activity on basic hop agronomy are very few and discontinuous as well. The objective of this article is to provide an overview of possible uses, phenology, and agronomic aspects of hops, with specific reference to the difficulties and opportunities this crop is experiencing in the new growing areas, under both conventional and organic farming. The present review aims to fill a void still existing for this topic in the literature and to give directions for farmers that want to face the cultivation of such a challenging crop.

Spikelet fertility and heat shock transcription factor (Hsf) gene responses to heat stress in tolerant and susceptible rice (Oryza sativa L.) genotypes

2019 ◽  
Vol 157 (04) ◽  
pp. 283-299 ◽  
Author(s):  
C. Malumpong ◽  
S. Cheabu ◽  
C. Mongkolsiriwatana ◽  
W. Detpittayanan ◽  
A. Vanavichit
Keyword(s):  
Heat Stress ◽  
Pollen Germination ◽  
Seed Set ◽  
Oryza Sativa L ◽  
Flag Leaf ◽  
Pollen Viability ◽  
Spikelet Fertility ◽  
Anther Dehiscence ◽  
Spikelet Sterility ◽  
Plant Parts

AbstractThe reproductive stage of rice is the most sensitive to heat stress, which can lead to spikelet sterility. Thus, heat-tolerant and heat-susceptible genotypes were used to investigate their differences in terms of phenotypic responses and expression changes of Hsf genes at the pre-flowering stage under heat stress. Results clearly showed that panicles had the highest temperature compared with other plant parts under both natural and heated conditions. However, the temperatures of tolerant and susceptible genotypes were not significantly different. In terms of spikelet fertility, the tolerant lines M9962 and M7988 had high seed set because their anther dehiscence, pollen viability and pollen germination were only slightly affected. In contrast, the susceptible line Sinlek showed severe effects at all steps of fertilization, and the pollen viability of M7766 was slightly affected under heat stress but was more affected in terms of anther dehiscence and pollen germination. Both susceptible lines showed dramatically decreased seed set. In addition, the expression of six HsfA genes in the flag leaves and spikelets at the R2 stage of plants under heat stress showed different responses. Notably, expression of the HsfA2a gene was predominantly upregulated in the flag leaf and spikelets under heat stress in M9962. Therefore, it can be concluded that heat stress has severe effects on the stamen, and that different genotypes have different susceptibilities to heat stress.

scholarly journals Prediction of zinc deficiency in navy beans (Phaseolus vulgaris) by soil and plant analyses

1990 ◽  
Vol 30 (4) ◽  
pp. 557 ◽  
Author(s):  
JD Armour ◽  
AD Robson ◽  
GSP Ritchie
Keyword(s):  
Phaseolus Vulgaris ◽  
Soil Solution ◽  
Relative Yield ◽  
Fresh Weight ◽  
Soil Tests ◽  
Plant Parts ◽  
Zn Concentration ◽  
Navy Beans ◽  
Glasshouse Experiment ◽  
Zn Status

Navy beans (Phaseolus vulgaris cv. Gallaroy) were grown with 7 rates of zinc (Zn) in a Zn-deficient gravelly sandy loam in a glasshouse experiment. The plant shoots were harvested 31 days after sowing and the Zn concentration in each of 4 plant parts (YL, young leaf; YOL, young open leaf; YFEL, youngest fully expanded leaf; and whole shoots) was related to the fresh weight of the shoots. The critical Zn concentrations (mgtkg) in the plant parts determined by the 2 intersecting straight lines model were 21.1 for YL (r2 = 0.66), 17.1 for YOL (r2 = 0.83), 10.6 for YFEL (r2 = 0.91) and 12.5 for the whole tops (r2 = 0.88). The YFEL was selected as an appropriate diagnostic tissue because it is readily identifiable in the field and had the highest 1.2 with fresh weight. In a second glasshouse experiment, the critical Zn concentration in the YFEL and 5 soil tests were evaluated for their ability to predict the Zn status of navy beans. There were 13 soils from sands to clays with a wide range of chemical properties. The soil tests were 0.1 mol/L HCl, DTPA, EDTA, dilute CaCl2 and soil solution Zn. The concentration of Zn in the YFEL correctly predicted Zn deficiency or adequacy in about 77% of samples. The results from both experiments showed that a critical Zn concentration of 10-11 mg/kg in the YFEL can be used to diagnose the Zn status of Gallaroy navy beans. It was not possible to recommend a single soil test for prediction of the relative yield of navy beans. A combination of quantity (HCl, EDTA, DTPA) and intensity (soil solution, 0.002 mol/L CaCl2, 0.01 mol/L CaCl2) parameters were able to explain most of the variation in the Zn concentration of the YFEL, a more sensitive measure of nutrient availability than relative yield. EDTA-Zn in combination with 0.01 mol/L CaCl2-Zn explained 90% of the variation in the Zn concentration in the YFEL, while HCl- or DTPA-Zn and 0.01 mol/L CaCl2 explained about 80% of the variation. As soil solution Zn was significantly correlated with 0.002 and 0.01 mol/L CaCl2-Zn (r = 0.75, P<0.01; r = 0.62, P<0.05, respectively), CaCl2-Zn may be used as a more convenient measure of Zn intensity than soil solution Zn.

scholarly journals Physiological and Productivity Responses of High-wire Tomato as Affected by Supplemental Light Source and Distribution within the Canopy

2016 ◽  
Vol 141 (2) ◽  
pp. 196-208 ◽  
Author(s):  
Celina Gómez ◽  
Cary A. Mitchell
Keyword(s):  
Photosynthetic Activity ◽  
Experimental Period ◽  
Fruit Yield ◽  
Tissue Temperature ◽  
Control Treatment ◽  
Fresh Weight ◽  
Tomato Production ◽  
Light Emitting ◽  
Plant Parts ◽  
Use Efficiency

The relative coolness-to-touch of light-emitting diodes (LEDs) has enabled commercial implementation of intracanopy lighting (ICL) in the greenhouse. Intracanopy lighting, which refers to the strategy of lighting along the side or from within the foliar canopy, can increase canopy photosynthetic activity, but physiological and productivity responses of high-wire greenhouse tomato (Solanum lycopersicum) to intracanopy supplemental lighting (SL) still are not yet fully understood. Two consecutive production experiments were conducted across seasons in a glass-glazed greenhouse located in a midnorthern, continental climate [lat. 40°N (West Lafayette, IN)]. Plants were grown from winter-to-summer [increasing solar daily light integral (DLI)] and from summer-to-winter (decreasing solar DLI) to compare three SL strategies for high-wire tomato production across changing solar DLIs: top lighting with high-pressure sodium lamps (HPS) vs. intracanopy LED vertical towers vs. hybrid SL (HPS + horizontal ICL-LEDs). A control treatment also was included for which no SL was provided. Supplemental DLI for each experimental period was adjusted monthly, to complement seasonal changes in sunlight, aiming to approach a target total DLI of 25 mol·m‒2·d‒1 during fruit set. Harvest parameters (total fruit fresh weight, number of fruit harvested, and average cluster fresh weight), tissue temperature, chlorophyll fluorescence, and stomatal conductance (gS) were unaffected by SL treatment in both experiments. Among the physiological parameters evaluated, CO2 assimilation measured under light-saturating conditions, light-limited quantum-use efficiency, and maximum gross CO2 assimilation (Amax) proved to be good indicators of how ICL reduces the top-to-bottom decline in leaf photosynthetic activity otherwise measured with top lighting only (HPS-SL or solar). Although SL generally increased fruit yield relative to control, lack of SL treatment differences among harvest parameters indicates that higher crop photosynthetic activity did not increase fruit yield. Compared with control, intracanopy SL increased yield to the same extent as top SL, but the remaining photoassimilate from ICL most likely was partitioned to maintain nonharvested, vegetative plant parts as well.

scholarly journals   Assimilatory function and biochemical changes in Stylosanthes hamata grown under elevated CO2

2012 ◽  
Vol 58 (No. 5) ◽  
pp. 224-229 ◽  
Author(s):  
M.J. Baig ◽  
R.K. Bhatt ◽  
H.S. Tiwari ◽  
P. Swami
Keyword(s):  
Biomass Production ◽  
Protein Profile ◽  
Photosynthetic Pigment ◽  
Protein Accumulation ◽  
Maximum Increase ◽  
Plant Parts ◽  
Stylosanthes Hamata ◽  
Use Efficiency ◽  
The Impact

We studied the impact of 360 &plusmn; 50 &micro;L/l (ambient) and 600 &plusmn; 50 &micro;L/L (elevated) CO<sub>2</sub> on growth performance, biomass production, photosynthetic efficiency, carbon isotope discrimination, protein profile and some antioxidant enzymes on Stylosanthes hamata. This crop responded significantly to photosynthetic rate, stomatal conductance and transpiration rate under elevated CO<sub>2</sub>. The biomass production in terms of fresh and dry was increased in elevated CO<sub>2</sub> by 126.81% (fresh) and 114.55% (dry) over ambient CO<sub>2</sub>. Long term exposure to elevated CO<sub>2</sub> enhanced photosynthetic water use efficiency by 127.77%. The photosynthetic pigment, total chlorophyll and chlorophyll a/b ratio also increased by 220.56 and 132.86%, respectively in elevated over ambient CO<sub>2</sub>. Around 149% increase in the soluble protein accumulation (mg/g FW) was recorded under elevated over ambient CO<sub>2</sub>, which was also reflected in the polyacrylamide gel profile. The isoforms of superoxide dismutase and esterase isozymes showed remarkable difference under elevated as compared to ambient. Measurement of <sup>13</sup>&delta; in different plant parts indicated a significant increase in discrimination against <sup>13</sup>C when plants were grown at elevated relative to ambient CO<sub>2</sub>. Maximum increase was recorded in roots (439.72%) followed by leaf and the stem recorded least increase in <sup>13</sup>&delta; (119.94%) in elevated over ambient CO<sub>2</sub>. &nbsp; &nbsp;

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