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1.
Bingzi Zhao Motohiko Kondo Morihiro Maeda Yasuo Ozaki Jiabao Zhang 《Plant and Soil》2004,261(1-2):61-75
A pot experiment was conducted in a glasshouse to clarify and quantify the effect of plant part, water regime, growth period, and cultivar on carbon isotope discrimination (CID), and to analyze the relationship between CID, stomatal behavior and water-use efficiency (WUE). The experiment was comprised of two upland rice (Oryza sativa L.) cultivars and three water regimes (100, 70, and 40% of saturation moisture) in a completely randomized design. Plants were harvested at tillering, flowering, and maturity. No significant cultivar differences in above-ground dry matter-based WUE (WUEA) and total dry matter-based WUE (WUET) were observed. WUEA (and WUET) increased with water stress up to tillering, but decreased with water stress after tillering. Significant cultivar differences in CID in all the analyzed plant parts were observed at all harvest times. Reduction in CID with water stress was greatest at tillering, and the effect was less pronounced at flowering and at maturity. At each harvest, the effect was most pronounced in newly developed plant parts. Root and grain tended to have the lowest CID values, and stem the highest, at all harvest times. A negative relationship was observed between CID measured at tillering and WUEA (and WUET) measured over the period from seedling to tillering, whereas a reverse relationship was obtained between CID measured at flowering and WUEA (and WUET) measured over the period from tillering to flowering, and an unclear relationship between CID measured at maturity and WUEA (and WUET) measured over the period from flowering to maturity. The ratio of the intercellular and atmospheric concentration of CO2 (Ci/Ca) were closely associated with CID throughout the water regimes when one cultivar was considered, however, cultivar differences in CID were not related to variations in Ci/Ca. The results indicate that significant cultivar difference existed in CID in all the analyzed plant parts at all harvest times, while corresponding difference in WUEA (and WUET) between the cultivars was not necessarily consistent. Abbreviations: WUE – water-use efficiency; WUEi – instantaneous WUE (or leaf transpiration efficiency); ADM – above-ground dry matter; TDM – total dry matter; WUEA– ADM-based WUE; WUET– TDM-based WUE} CID – carbon isotope discrimination; NL – the newest leaves; FEL – recently fully expanded leaves; FL – flag leaves; P – photosynthesis rate; g – leaf stomatal conductance to water vapor; Ci– intercellular CO2 concentration; Ca– atmospheric CO2 concentration; T – transpiration rate; gs – total conductance of CO2 相似文献
2.
Federico Triana Nicoletta Nassi o Di Nasso Giorgio Ragaglini Neri Roncucci Enrico Bonari 《Global Change Biology Bioenergy》2015,7(4):811-819
Giant reed (Arundo donax L.) and miscanthus (Miscanthus × giganteus Greef et Deu.) are two perennial rhizomatous grasses (PRGs), considered as promising sources of lignocellulosic biomass for renewable energy production. Although the agronomic performance of these species has been addressed by several studies, the literature dedicated to the crop water use of giant reed and miscanthus is still limited. Our objective was thus to investigate giant reed and miscanthus water use by assessing crop evapotranspiration (ETc), crop coefficients (Kc) and water use efficiency (WUE). The study was carried out in central Italy and specifically designed water-balance lysimeters were used to investigate the water use of these PRGs during the 2010 and 2011 growing seasons. Giant reed showed the highest cumulative evapotranspiration, with an average consumption of approximately 1100 mm, nearly 20% higher than miscanthus (900 mm). Crop evapotranspiration rates differed significantly between the species, particularly during the midseason (from June to September), when average daily ETc was 7.4 and 6.2 mm in giant reed and miscanthus respectively. The Kc values determined in our study varied from 0.4 to 1.9 for giant reed and 0.3 to 1.6 for miscanthus. Finally, WUE was higher in miscanthus than in giant reed, with average values of 4.2 and 3.1 g L−1 respectively. Further studies concerning water use under nonoptimal water conditions should be carried out and an assessment of the response to water stress of both crops is necessary to integrate the findings from this study. 相似文献
3.
Michael Robben Ethan Thibault Michaellong Tran Yajun Wu Arvid Boe Jose L. Gonzalez-Hernandez 《Bioenergy Research》2018,11(1):106-114
The salt-tolerant capability of the candidate bioenergy crop prairie cordgrass greatly surpasses that of previously characterized prairie grass species and most other plants. To understand the mechanism of inherited salt tolerance, we compared phenotypic and genetic qualities in half-sib families of prairie cordgrass after salt treatment. Each family was treated with a 400 mM NaCl solution or a water control and then measured for various health phenotypes. Phenotypes associated with salt tolerance were shown to be moderately heritable between parent and offspring. RNA-seq analysis revealed differential regulation in unique pathways including metabolism, signaling, photosynthesis, and the circadian rhythm. The studies herein suggest that alternative regulation of the photosynthetic pathway could confer increased salt resistance in halophytes and can be monitored phenotypically or genetically in breeding programs. The improvement of salt-tolerant traits in prairie cordgrass would increase its potential to be grown as a bioenergy crop on lands that are not suitable for the growth of food crops. 相似文献
4.
Enhanced evapotranspiration was observed during extreme drought from Miscanthus,opposite of other crops
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Eva Joo Marcelo Zeri Mir Zaman Hussain Evan H. DeLucia Carl J. Bernacchi 《Global Change Biology Bioenergy》2017,9(8):1306-1319
The impact of extreme drought and heat stress that occurred in the Midwestern U.S. in 2012 on evapotranspiration (ET), net ecosystem productivity (NEP), and water‐use efficiency (WUE) of three perennial ecosystems (switchgrass, miscanthus, prairie) and a maize/soybean agroecosystem was studied as part of a long‐term experiment. Miscanthus had a slower initial response but an eventually drastic ET as drought intensified, which resulted in the largest water deficit among the crops. The substantially higher ET at peak drought was likely supplied by access to deep soil water, but suggests that stomatal conductance of miscanthus during the drought may respond differently than the other ecosystems, consistent with an anisohydric strategy. While there was a discrepancy in the water consumption of maize and switchgrass/prairie in the early time of drought, all these ecosystems followed a water‐saving strategy when drought intensified. The gross primary production (GPP) of miscanthus dropped, but was reversible, when temperature reached 40 °C and still provided the largest total GPP among the ecosystems. Increased ET for miscanthus during 2012 resulted a large decline in ecosystem WUE compared to what was observed in other years. The biophysical responses of miscanthus measured during an extreme, historic drought suggest that this species can maintain high productivity longer than other ecosystems during a drought at the expense of water use. While miscanthus maintained productivity during drought, recovery lagged associated with depleted soil moisture. The enhanced ET of miscanthus may intensify droughts through increase supply of deep soil moisture to the atmosphere. 相似文献
5.
Cao X Jia JB Li H Li MC Luo J Liang ZS Liu TX Liu WG Peng CH Luo ZB 《Plant biology (Stuttgart, Germany)》2012,14(4):612-620
Although fast‐growing Populus species consume a large amount of water for biomass production, there are considerable variations in water use efficiency (WUE) across different poplar species. To compare differences in growth, WUE and anatomical properties of leaf and xylem and to examine the relationship between photosynthesis/WUE and anatomical properties of leaf and xylem, cuttings of six poplar species were grown in a botanical garden. The growth performance, photosynthesis, intrinsic WUE (WUEi), stable carbon isotope composition (δ13C) and anatomical properties of leaf and xylem were analysed in these poplar plants. Significant differences were found in growth, photosynthesis, WUEi and anatomical properties among the examined species. Populus cathayana was the clone with the fastest growth and the lowest WUEi/δ13C, whereas P. × euramericana had a considerable growth increment and the highest WUEi/δ13C. Among the analysed poplar species, the highest total stomatal density in P. cathayana was correlated with its highest stomatal conductance (gs) and lowest WUEi/δ13C. Moreover, significant correlations were observed between WUEi and abaxial stomatal density and stem vessel lumen area. These data suggest that photosynthesis, WUEi and δ13C are associated with leaf and xylem anatomy and there are tradeoffs between growth and WUEi. It is anticipated that some poplar species, e.g. P. × euramericana, are better candidates for water‐limited regions and others, e.g. P. cathayana, may be better for water‐abundant areas. 相似文献
6.
Abstact Twelve randomly chosen Stipa tenacissima L. individuals were grouped into three tussock size classes, small (ST), medium (MT), and large (LT) with 5.6±0.8, 34.1±4.2,
and 631.9±85.8 g of dry green foliar matter, respectively, in three plots with different S. tenacissima cover. Instantaneous (WUEi) and long-term (WUEl) water-use efficiencies were measured in two seasons of contrasting volumetric soil water content (early winter 21.0±0.8
% and summer 5.8±0.3 %). Maximum photochemical efficiency of photosystem 2 and stomatal conductance in summer assessed the
extent of water and irradiance stress in tussocks of different size. WUEi was lower in MT and ST “water spender” strategies than in LT during the high water-availability season. In summer net photosynthetic
rate and WUEi were higher and photoinhibition was lower in LT than in MT and ST. Significant spatial variability was found in WUEi. Water uptake was competitive in stands with denser alpha grass and more water availability in summer, reducing their WUEi. However, WUEl showed a rising tendency when water became scarce. Thus it is important to explicitly account for plant size in ecophysiological
studies, which must be combined with demographic information when estimating functional processes at stand level in sequential
scaling procedures. 相似文献
7.
Carbon isotope composition,water-use efficiency and biomass productivity of Eucalyptus microtheca populations under different water supplies 总被引:3,自引:0,他引:3
Variation in carbon isotope composition (δ13C), water-use efficiency (WUE) and biomass productivity were compared among three populations of Eucalyptus microtheca F.
Muell. in a greenhouse. Seedlings were maintained under one well-watered (Control, keeping the soil at field capacity) and
two different water deficit conditions (Drought stress I, keeping the same soil water content; Drought stress II, keeping
the same soil water supply). In each treatment, significant population differences in δ13C, WUE, and dry matter accumulation and allocation were detected. A negative correlation between WUE and biomass productivity
was detected under control and drought stress I, but a positive correlation under drought stress II. The results suggested
that there were different water-use strategies among the populations, the southeastern population with lower WUE may employ
a prodigal water-use strategy, whereas the northwestern and central populations with higher WUE may employ a conservative
water-use strategy. This knowledge may be useful as criteria for genotype selection within a breeding program for this species.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
8.
The bioeconomy, with its aim of replacing fossil by biobased resources, is increasingly focusing on biomass production from perennial crops, such as miscanthus. To date, research on miscanthus has explored a number of cultivation aspects; however, one major issue has not yet been addressed: How can former miscanthus fields be reintegrated into a crop rotation? This encompasses the questions of which following crop most efficiently suppresses resprouting miscanthus and what happens to the soil nitrogen content after a miscanthus removal. This study aimed to answer both questions. For this purpose, four spring crops (ryegrass, rapeseed, barley, maize) and fallow as control were cultivated after a Miscanthus sinensis removal. To test the effect of the removal on soil nitrogen content, each spring crop (excluding fallow) was divided into fertilized and unfertilized plots. After the spring crop harvest, winter wheat was cultivated to clarify which spring crop had most efficiently suppressed the resprouting miscanthus. The results indicate that fertilized crops had 35% less miscanthus biomass per hectare than unfertilized crops, probably due to the higher plant density and/or better development of the fertilized crops during the growing season. The soil mineral nitrogen (Nmin) content was found to increase during the vegetation period following the miscanthus removal (average +14.85 kg/ha), but was generally on a low level. We conclude that nitrogen from miscanthus residues is partly fixed in organic matter and is thus not plant‐available in the first cropping season. As some nitrogen is supplied by the decomposition of miscanthus residues, our results suggest that the crop cultivated after a miscanthus removal requires less fertilization. Of all the follow‐on spring crops tested, maize coped with the prevailing soil conditions and resprouting miscanthus most efficiently, resulting in satisfactory yields, and thus seems to be a suitable crop for cultivation after miscanthus. 相似文献
9.
Brandon M. Strange Russell K. Monson Paul Szejner Jim Ehleringer Jia Hu 《Global Change Biology》2023,29(15):4354-4367
The US Southwest has been entrenched in a two-decade-long megadrought (MD), the most severe since 800 CE, which threatens the long-term vitality and persistence of regional montane forests. Here, we report that in the face of record low winter precipitation and increasing atmospheric aridity, seasonal activity of the North American Monsoon (NAM) climate system brings sufficient precipitation during the height of the summer to alleviate extreme tree water stress. We studied seasonally resolved, tree-ring stable carbon isotope ratios across a 57-year time series (1960–2017) in 17 Ponderosa pine forests distributed across the NAM geographic domain. Our study focused on the isotope dynamics of latewood (LW), which is produced in association with NAM rains. During the MD, populations growing within the core region of the NAM operated at lower intrinsic and higher evaporative water-use efficiencies (WUEi and WUEE, respectively), compared to populations growing in the periphery of the NAM domain, indicating less physiological water stress in those populations with access to NAM moisture. The disparities in water-use efficiencies in periphery populations are due to a higher atmospheric vapor pressure deficit (VPD) and reduced access to summer soil moisture. The buffering advantage of the NAM, however, is weakening. We observed that since the MD, the relationship between WUEi and WUEE in forests within the core NAM domain is shifting toward a drought response similar to forests on the periphery of the NAM. After correcting for past increases in the atmospheric CO2 concentration, we were able to isolate the LW time-series responses to climate alone. This showed that the shift in the relation between WUEi and WUEE was driven by the extreme increases in MD-associated VPD, with little advantageous influence on stomatal conductance from increases in atmospheric CO2 concentration. 相似文献
10.
X. P. Sun H. L. Yan P. Ma B. H. Liu Y. J. Zou D. Liang F. W. Ma P. M. Li 《Photosynthetica》2012,50(4):501-507
We studied photosynthetic capacity, growth, sap flow, and water-use efficiency in young trees of ‘Pink Lady’ apple (Malus domestica) that were exposed to 60 d of moisture stress. Three irrigation schemes were tested in the greenhouse: well-watered control; drought; or alternate deficit irrigation (ADI). Compared with the drought-stressed plants, those treated via ADI showed better height growth, larger scion diameters, and greater total leaf area, as well as significantly increased gains in dry biomass and rootstock diameters. However, their performance was still significantly lower than that demonstrated by continuously well-watered plants. Sap flow was greater under ADI than under drought, but less than under control conditions. The average rate of net photosynthesis, total amount of irrigation water applied, and dry biomass gain had highly significant and positive linear correlations with long-term water-use efficiency (WUEL). The same was true between average stomatal conductance and WUEL. By contrast, instantaneous water-use efficiency (WUEI) was very significantly and negatively correlated with WUEL. In addition, values for WUEL were much higher from well-watered plants when compared with either drought-stressed trees or those treated per ADI. Therefore, our results indicate that, although ‘Pink Lady’ apple normally has high WUE, it still consumes a large amount of water. Therefore, the practice of ADI following a period of long-term drought could be used to improve growth and WUEL by this cultivar. 相似文献
11.
Sarah C. Davis William J. Parton Frank G. Dohleman Candice M. Smith Stephen Del Grosso Angela D. Kent Evan H. DeLucia 《Ecosystems》2010,13(1):144-156
We evaluated the biogeochemical cycling and relative greenhouse gas (GHG) mitigation potential of proposed biofuel feedstock
crops by modeling growth dynamics of Miscanthus × giganteus Greef et Deuter (miscanthus), Panicum virgatum L. (switchgrass), Zea mays L. (corn), and a mixed prairie community under identical field conditions. DAYCENT model simulations for miscanthus were
parameterized with data from trial plots in Europe and Illinois, USA. Switchgrass, corn, and prairie ecosystems were simulated
using parameters published in the literature. A previously unknown source of nitrogen (N) was necessary to balance the plant
nutrient budget in miscanthus crops, leading us to hypothesize that miscanthus growth depends on N-fixation. We tested for
nitrogenase activity by acetylene reduction of whole rhizomes and bacteria isolated from the rhizosphere and miscanthus tissue.
Our results supported the hypothesis that biological N-fixation contributed to the N demand of miscanthus, a highly productive
perennial grass. Corn agro-ecosystems emit 956 to 1899 g CO2eq m−2y−1 greater GHGs (including CO2, N2O, CH4) to the atmosphere than the other biofuel crop alternatives because of greater N2O emissions from fertilizer additions. Of the feedstock crops evaluated in this study, miscanthus would result in the greatest
GHG reduction. 相似文献
12.
Water use efficiency in C3 cereals under Mediterranean conditions: a review of physiological aspects
In this review, we will discuss physiological traits of C3 cereals related to water use efficiency (WUE) in Mediterranean environments, from leaf (WUEinstantaneous) to crop level (WUEyield or ‘water productivity’). First, we analyse the WUEinstantaneous and the possible trade‐off between improving this parameter and growth/yield performance. Ways to ameliorate WUE without penalties are discussed. We also analyse in what cases breeding by high or low WUEinstantaneous is a suitable criterion to maintain grain yield under drought (Mediterranean) conditions. This question is approached in the framework of carbon isotope discrimination, (Δ13C), the main indirect parameter used to integrate (at time and space scale) the WUEinstantaneous in C3 plants. A negative correlation between these two parameters has been confirmed by several studies. The relationship between Δ13C and grain yield, however, is more complex, and may differ from one environment to another. In Mediterranean conditions with moderate or no water stress, a positive correlation between Δ13C and grain yield is found in barley and wheat, whereas in ‘stored‐water’ crops (such as in some regions of Australia), lower Δ13C (i.e. higher WUEinstantaneous) is associated with higher grain yield, particularly in more stressful conditions. These apparent inconsistencies and their possible implications for plant breeding are discussed. One physiological trait that has received minor attention in attempts to improve WUEinstantaneous is the role of ear photosynthesis. Ears of barley and durum wheat have a higher WUEinstantaneous than the flag leaf, both in well‐watered and in drought conditions. The underlying causes of the higher WUEinstantaneous of ears are not fully understood, but their refixation capacity (i.e. the capacity to re‐assimilate respired carbon dioxide) could be important. Although the genotypic variability of this trait has not been extensively studied, some data support the idea that variation in refixation capacity may be attributable to genetic factors. At the crop level, decreasing soil evaporation is a crucial factor in efforts to improve the WUEyield in Mediterranean conditions, and fast initial growth of the crop (i.e. early vigour) seems to be relevant. In wheat, modern varieties with dwarfing genes (giberellic acid – insensitive) have higher yields but, concomitantly, they have lower initial growth performance. Recently, semi‐dwarf cultivars (giberellic acid – sensitive) with high grain yield and simultaneously high early vigour were found, opening new avenues to increase WUEyield in wheat. The negative effects of futile water loss by cuticular and nocturnal transpiration are also commented. Finally, we discuss some agronomic practices (in particular, ‘deficit irrigation’ systems) linked to physiological traits that confer higher WUEyield,, in particular, in the cases of Mediterranean regions. 相似文献
13.
Root growth and water uptake in winter wheat under deficit irrigation 总被引:20,自引:0,他引:20
Root growth is critical for crops to use soil water under water-limited conditions. A field study was conducted to investigate the effect of available soil water on root and shoot growth, and root water uptake in winter wheat (Triticum aestivum L.) under deficit irrigation in a semi-arid environment. Treatments consisted of rainfed, deficit irrigation at different developmental stages, and adequate irrigation. The rainfed plots had the lowest shoot dry weight because available soil water decreased rapidly from booting to late grain filling. For the deficit-irrigation treatments, crops that received irrigation at jointing and booting had higher shoot dry weight than those that received irrigation at anthesis and middle grain filling. Rapid root growth occurred in both rainfed and irrigated crops from floral initiation to anthesis, and maximum rooting depth occurred by booting. Root length density and dry weight decreased after anthesis. From floral initiation to booting, root length density and growth rate were higher in rainfed than in irrigated crops. However, root length density and growth rate were lower in rainfed than in irrigated crops from booting to anthesis. As a result, the difference in root length density between rainfed and irrigated treatments was small during grain filling. The root growth and water use below 1.4 m were limited by a caliche (45% CaCO3) layer at about 1.4 m profile. The mean water uptake rate decreased as available soil water decreased. During grain filling, root water uptake was higher from the irrigated crops than from the rainfed. Irrigation from jointing to anthesis increased seasonal evapotranspiration, grain yield, harvest index and water-use efficiency based on yield (WUE), but did not affect water-use efficiency based on aboveground biomass. There was no significant difference in WUE among irrigation treatments except one-irrigation at middle grain filling. Due to a relatively deep root system in rainfed crops, the higher grain yield and WUE in irrigated crops compared to rainfed crops was not a result of rooting depth or root length density, but increased harvest index, and higher water uptake rate during grain filling. 相似文献
14.
Patrick Z. Ellsworth Max J. Feldman Ivan Baxter Asaph B. Cousins 《The Plant journal : for cell and molecular biology》2020,102(6):1234-1248
Genetic selection for whole‐plant water use efficiency (yield per transpiration; WUEplant) in any crop‐breeding programme requires high‐throughput phenotyping of component traits of WUEplant such as intrinsic water use efficiency (WUEi; CO2 assimilation rate per stomatal conductance). Measuring WUEi by gas exchange measurements is laborious and time consuming and may not reflect an integrated WUEi over the life of the leaf. Alternatively, leaf carbon stable isotope composition (δ13Cleaf) has been suggested as a potential time‐integrated proxy for WUEi that may provide a tool to screen for WUEplant. However, a genetic link between δ13Cleaf and WUEplant in a C4 species has not been well established. Therefore, to determine if there is a genetic relationship in a C4 plant between δ13Cleaf and WUEplant under well watered and water‐limited growth conditions, a high‐throughput phenotyping facility was used to measure WUEplant in a recombinant inbred line (RIL) population created between the C4 grasses Setaria viridis and S. italica. Three quantitative trait loci (QTL) for δ13Cleaf were found and co‐localized with transpiration, biomass accumulation, and WUEplant. Additionally, WUEplant for each of the δ13Cleaf QTL allele classes was negatively correlated with δ13Cleaf, as would be predicted when WUEi influences WUEplant. These results demonstrate that δ13Cleaf is genetically linked to WUEplant, likely to be through their relationship with WUEi, and can be used as a high‐throughput proxy to screen for WUEplant in these C4 species. 相似文献
15.
GEORGE C. HICKMAN ANDY VANLOOCKE FRANK G. DOHLEMAN CARL J. BERNACCHI 《Global Change Biology Bioenergy》2010,2(4):157-168
In the Midwestern US, perennial rhizomatous grasses (PRGs) are considered one of the most promising vegetation types to be used as a cellulosic feedstock for renewable energy production. The potential widespread use of biomass crops for renewable energy production has sparked numerous environmental concerns, including the impacts of land‐use change on the hydrologic cycle. We predicted that total seasonal evapotranspiration (ET) would be higher for PRGs relative to maize resulting from higher leaf area and a prolonged growing season. We further predicted that, compared with maize, higher aboveground biomass associated with PRGs would offset the higher ET and increase water‐use efficiency (WUE) in the context of biomass harvests for liquid biofuel production. To test these predictions, ET was estimated during the 2007 growing season for replicated plots of Miscanthus×giganteus (miscanthus), Panicum virgatum (switchgrass), and Zea mays (maize) using a residual energy balance approach. The combination of a 25% higher mean latent heat flux (λET) and a longer growing season resulted in miscanthus having ca. 55% higher cumulative ET over the growing season compared with maize. Cumulative ET for switchgrass was also higher than maize despite similar seasonal‐mean λET. Based on total harvested aboveground biomass, WUE was ca. 50% higher for maize relative to miscanthus; however, when WUE calculated from only maize grain biomass was compared with WUE calculated from miscanthus harvested aboveground biomass, this difference disappeared. Although WUE between maize and miscanthus differed postsenescence, there were no differences in incremental WUE throughout the growing season. Despite initial predictions, aboveground biomass for switchgrass was less than maize; thus WUE was substantially lower for switchgrass than for either maize scenario. These results indicate that changes in ET due to large‐scale implementation of PRGs in the Midwestern US would likely influence local and regional hydrologic cycles differently than traditional row crops. 相似文献
16.
Balasaheb V. Sonawane Asaph B. Cousins 《The Plant journal : for cell and molecular biology》2020,103(4):1590-1602
Breeding economically important C4 crops for enhanced whole‐plant water‐use efficiency (WUEplant) is needed for sustainable agriculture. WUEplant is a complex trait and an efficient phenotyping method that reports on components of WUEplant, such as intrinsic water‐use efficiency (WUEi, the rate of leaf CO2 assimilation relative to water loss via stomatal conductance), is needed. In C4 plants, theoretical models suggest that leaf carbon isotope composition (δ13C), when the efficiency of the CO2‐concentrating mechanism (leakiness, ?) remains constant, can be used to screen for WUEi. The limited information about how ? responds to water limitations confines the application of δ13C for WUEi screening of C4 crops. The current research aimed to test the response of ? to short‐ or long‐term moderate water limitations, and the relationship of δ13C with WUEi and WUEplant, by addressing potential mesophyll CO2 conductance (gm) and biochemical limitations in the C4 plant Sorghum bicolor. We demonstrate that gm and ? are not responsive to short‐ or long‐term water limitations. Additionally, δ13C was not correlated with gas‐exchange estimates of WUEi under short‐ and long‐term water limitations, but showed a significant negative relationship with WUEplant. The observed association between the δ13C and WUEplant suggests an intrinsic link of δ13C with WUEi in this C4 plant, and can potentially be used as a screening tool for WUEplant in sorghum. 相似文献
17.
This study compared mature Eucalyptus kochii subsp. plenissima trees in inner regions or edges of natural bushland to young trees belt-planted through cleared agricultural land as uncut saplings or regenerating coppice over 2.7 years at Kalannie, Western Australia (320 mm annual rainfall). We assessed the ability of the species to alter its gas exchange characteristics, leaf physical attributes, and water-use efficiency of foliar carbon assimilation (WUE i) or of total dry matter production (WUE DM). Stomatal conductance (g s) varied five-fold between treatment means, with coppices exhibiting greatest values and mature bush least. Photosynthetic rates followed this trend. Leaf photosynthetic capacity estimated by chlorophyll content varied 1.3-fold parallel with variations in leaf thickness, with coppices rating lowest and mature edge trees most highly. WUE i varied 1.5-fold between treatments and was greatest in mature inner-bush and edge trees. Leaf photosynthetic capacity and g s were both correlated with WUE i. Carbon isotope composition (δ13C values) of new shoot dry matter produced early in a seasonal flush were similar to those of root starch but when averaged over the whole season correlated well with WUE i and gas exchange characteristics of trees of each treatment. Coppices showed poorest WUE i and most negative shoot tip δ13C but their WUE DM was high. This discrepancy was suggested to relate to carbon allocation strategies in coppices favouring fast growth of replacement shoots but not of roots. Physiology of coppice growth of E. kochii is usefully geared towards both rapid and water-use efficient production of woody biomass in water limited environments. 相似文献
18.
Background and Aims
During the Mesozoic, the polar regions supported coniferous forests that experienced warm climates, a CO2-rich atmosphere and extreme seasonal variations in daylight. How the interaction between the last two factors might have influenced water use of these conifers was investigated. An experimental approach was used to test the following hypotheses: (1) the expected beneficial effects of elevated [CO2] on water-use efficiency (WUE) are reduced or lost during the 24-h light of the high-latitude summer; and (2) elevated [CO2] reduces plant water use over the growing season.Methods
Measurements of leaf and whole-plant gas exchange, and leaf-stable carbon isotope composition were made on one evergreen (Sequoia sempervirens) and two deciduous (Metasequoia glyptostroboides and Taxodium distichum) ‘living fossil’ coniferous species after 3 years'' growth in controlled-environment simulated Cretaceous Arctic (69°N) conditions at either ambient (400 µmol mol−1) or elevated (800 µmol mol−1) [CO2].Key Results
Stimulation of whole-plant WUE (WUEP) by CO2 enrichment was maintained over the growing season for the three studied species but this pattern was not reflected in patterns of WUE inferred from leaf-scale gas exchange measurements (iWUEL) and δ13C of foliage (tWUEL). This response was driven largely by increased rates of carbon uptake, because there was no overall CO2 effect on daily whole-plant transpiration or whole-plant water loss integrated over the study period. Seasonal patterns of tWUEL differed from those measured for iWUEL. The results suggest caution against over simplistic interpretations of WUEP based on leaf isotopic composition.Conclusions
The data suggest that the efficiency of whole-tree water use may be improved by CO2 enrichment in a simulated high-latitude environment, but that transpiration is relatively insensitive to atmospheric CO2 in the living fossil species investigated.Key words: Water-use efficiency, elevated CO2, living fossil plants, conifers, paleoecology, ancient polar forests, stable carbon isotopes, stomatal conductance, canopy transpiration 相似文献19.
Michael Abraha Ilya Gelfand Stephen K. Hamilton Changliang Shao Yahn-Jauh Su G. Philip Robertson Jiquan Chen 《Ecosystems》2016,19(6):1001-1012
Carbon and water exchanges between vegetated land surfaces and the atmosphere reveal the ecosystem-scale water-use efficiency (WUE) of primary production. We examined the interacting influence of dominant plant functional groups (C3 and C4) and land-use history on WUEs of annual corn and perennial (restored prairie, switchgrass and smooth brome grass) grasslands in the US Midwest from 2010 through 2013. To this end, we determined ecosystem-level (eWUE) and intrinsic (iWUE) WUEs using eddy covariance and plant carbon isotope ratios, respectively. Corn, switchgrass, and restored prairie were each planted on lands previously managed as grasslands under the USDA Conservation Reserve Program (CRP), or as corn/soybean rotation under conventional agriculture (AGR), while a field of smooth brome grass remained in CRP management. The iWUEs of individual C3 plant species varied little across years. Corn had the highest (4.1) and smooth brome grass the lowest (2.3) overall eWUEs (g C kg?1 H2O) over the 4 years. Corn and switchgrass did not consistently show a significant difference in seasonal eWUE between former CRP and AGR lands, whereas restored prairie had significantly higher seasonal eWUE on former AGR than on former CRP land due to a greater shift from C3 to C4 species on the former AGR land following a drought in 2012. Thus, differences in grassland eWUE were largely determined by the relative dominance of C3 and C4 species within the plant communities. In this humid temperate climate with common short-term and occasional long-term droughts, it is likely that mixed grasslands will become increasingly dominated by C4 grasses over time, with higher yields and eWUE than C3 plants. These results inform models of the interaction between carbon and water cycles in grassland ecosystems under current and future climate and management scenarios. 相似文献
20.
Critical responses of photosynthetic efficiency of goldspur apple tree to soil water variation in semiarid loess hilly area 总被引:4,自引:0,他引:4
Goldspur apple (Malus pumila cv. Goldspur) is one of the main fruit trees planted in semiarid loess hilly areas. The photosynthetic efficiency in leaves
of eight-year-old trees were studied under different soil water conditions with a Li-6400 portable photosynthesis system and a Li-Cor1600 portable steady state porometer in order to explore the effects of soil water stress on photosynthesis and the suitable soil
water content (SWC) for water-saving irrigation of apple orchards. The results showed that the leaf net photosynthetic rate
(P
N), transpiration rate (E), water-use efficiency (WUE), stomatal conductance (g
s), intercellular CO2 concentration (C
i), and stomatal limiting value (L
s) displayed different threshold responses to soil water variation. When SWC was within a range of about 60%–86% of field capacity
(FC), P
N and E were maintained in a relative steady state. At an elevated level but below 60% of FC, both P
N and E decreased evidently with decreasing soil moisture. The SWC needed to support WUE in a relatively steady state and at a high
level was in the range of about 50%–71% of FC. When SWC was less than 48% of FC, g
s and L
s declined with decreasing soil moisture, while C
i increased rapidly. Based on the analysis of the stomatal limitation of photosynthesis using two criteria (C
i and L
s) suggested by Farquhar and Sharkey, it was implied that the predominant cause of restricting P
N had changed from stomatal limitation to nonstomatal one under severe water stress. In terms of water-saving irrigation for
enhancing water-use efficiency, it was concluded that in semiarid loess hilly areas, the suitable range of SWC for water-saving
irrigation in goldspur apple orchards is in the range of about 50%–71% of FC, and the most severe degree of soil water stress
tolerated for photosynthesis is about 48% of FC. 相似文献