Various responses of sunflower genotypes to water stress on newly reclaimed sandy soil

2013 ◽  
Vol 61 (1) ◽  
pp. 55-69
Author(s):  
A. Salem ◽  
A. Omar ◽  
M. Ali
Keyword(s):  
Water Stress ◽  
Water Content ◽  
Transpiration Rate ◽  
Leaf Water ◽  
Oil Yield ◽  
Leaf Water Content ◽  
Growth Stages ◽  
Severe Drought ◽  
Water Supplies ◽  
Water Regimes

Water stress is a severe limitation for crop growth especially in arid and semi-arid regions of the world, as it has a vital role in plant growth and development at all growth stages. The aim of the present study was to evaluate the differential responses of twelve sunflower genotypes to three levels of water supply and select the most suitable one for such conditions. Two field experiments were conducted under adequate (7140 m3/ha), moderate (4760 m3/ha) and severe (2380 m3/ha) water regimes to evaluate the chlorophyll index, transpiration rate, leaf water content, plant height, head diameter, seeds/head, 1000-seed weight, seed and oil yield of the genotypes. Moderate and severe levels of drought had a significant impact on the transpiration rate, leaf water content, yield-contributing characters and oil yield of all the sunflower genotypes. However, the sunflower genotypes showed different responses to the different water regimes. The highest seed and oil yields were attained in L990 and Giza 102 in the case of adequate water supplies, while L38 was the best under moderate and severe drought conditions. On the basis of the results, sunflower genotype L990 could be recommended for growing when adequate water supplies are available, and L38 under moderate and severe water regimes to obtain high seed and oil yields.

scholarly journals Estimating Vertical Distribution of Leaf Water Content within Wheat Canopies after Head Emergence

2021 ◽  
Vol 13 (20) ◽  
pp. 4125
Author(s):  
Weiping Kong ◽  
Wenjiang Huang ◽  
Lingling Ma ◽  
Lingli Tang ◽  
Chuanrong Li ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Water Content ◽  
Near Infrared ◽  
Field Experiments ◽  
Estimation Method ◽  
Middle Layer ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Growth Stages ◽  
Spectral Indices

Monitoring vertical profile of leaf water content (LWC) within wheat canopies after head emergence is vital significant for increasing crop yield. However, the estimation of vertical distribution of LWC from remote sensing data is still challenging due to the effects of wheat spikes and the efficacy of sensor measurement from the nadir direction. Using two-year field experiments with different growth stages after head emergence, N rates, wheat cultivars, we investigated the vertical distribution of LWC within canopies, the changes of canopy reflectance after spikes removal, the relationship between spectral indices and LWC in the upper-, middle- and bottom-layer. The interrelationship among vertical LWC were constructed, and four ratio of reflectance difference (RRD) type of indices were proposed based on the published WI and NDWSI indices to determine vertical distribution of LWC. The results indicated a bell shape distribution of LWC in wheat plants with the highest value appeared at the middle layer, and significant linear correlations between middle-LWC vs. upper-LWC and middle-LWC vs. bottom-LWC (r ≥ 0.92) were identified. The effects of wheat spikes on spectral reflectance mainly occurred in near infrared to shortwave infrared regions, which then decreased the accuracy of LWC estimation. Spectral indices at the middle layer outperformed the other two layers in LWC assessment and were less susceptible to wheat spikes effects, in particular, the newly proposed narrow-band WI-4 and NDWSI-4 indices exhibited great potential in tracking the changes of middle-LWC (R2 = 0.82 and 0.84, respectively). By taking into account the effects of wheat spikes and the interrelationship of vertical LWC within canopies, an indirect induction strategy was developed for modeling the upper-LWC and bottom-LWC. It was found that the indirect induction models based on the WI-4 and NDWSI-4 indices were more effective than the models obtained from conventional direct estimation method, with R2 of 0.78 and 0.81 for the upper-LWC estimation, and 0.75 and 0.74 for the bottom-LWC estimation, respectively.

Methodological aspects and experimental conditions in the use of fluorescence as an index of water stress in cut leaves from genus Vitis

OENO One ◽  
1992 ◽  
Vol 26 (3) ◽  
pp. 163
Author(s):  
Francesco Iacono ◽  
Massimo Bertamini ◽  
Tardáguila Javier
Keyword(s):  
Water Stress ◽  
Water Content ◽  
Fluorescence Emission ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Variable Fluorescence ◽  
Experimental Conditions ◽  
Breeding Programmes ◽  
Methodological Aspects ◽  
Cut Leaves

<p style="text-align: justify;">Fluorescence emission is linked to leaf physiological conditions. In particular water stress modifies emission curves strongly. But fluorescence is also influenced by some factors which usually arise in experimental vine breeding programmes. The present research studies some variables that usually characterize the trials on genus <em>Vitis</em>: rootstocks and graftings.</p><p style="text-align: justify;">The time of measurement is very important and the fluorescence variables (absolute value) are not correlated with leaf water content. It needs a standardisation by time. The gross relation between fluorescence (after standardisation) and RWC is significant but it is modified by the rootstock behaviour. The Variable Fluorescence is strongly linked to leaf water content, even though the Maximum rate of Fluorescence Quenching shows a variable correlation with decreasing RWC. The genotype controls that variable better than Variable Fluorescence.</p>

scholarly journals Osmotic Potential, Sucrose Level, and Activity of Sucrose Metabolic Enzymes in Tall Fescue in Response to Deficit Irrigation

2010 ◽  
Vol 135 (6) ◽  
pp. 506-510 ◽  
Author(s):  
Jinmin Fu ◽  
Bingru Huang ◽  
Jack Fry
Keyword(s):  
Drought Stress ◽  
Water Content ◽  
Tall Fescue ◽  
Osmotic Potential ◽  
Deficit Irrigation ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Severe Drought ◽  
The Impact ◽  
Sucrose Level

Effects of deficit irrigation applied to home lawns, used as means of water conservation, are an important issue. However, the impact of deficit irrigation on sucrose metabolism in tall fescue (Festuca arundinacea) is unknown and important because sucrose is the dominant form of carbohydrate transported to developing plant organs. The objectives of this study were to investigate the effects of deficit irrigation on leaf water content, osmotic potential (ψS), sucrose level, and the activity of sucrose phosphate synthase (SPS; EC 2.4.1.14), sucrose synthase (SS; EC 2.4.1.13), and acid invertase (AI; EC 3.2.1.26) in tall fescue leaves. Sods of ‘Falcon II’ tall fescue were established in polyvinylchloride (PVC) tubes (10 cm diameter × 40 cm long) filled with a mixture of sand and fritted clay [9:1 (v:v)] and then placed in growth chambers. Reference evapotranspiration rate [ETo (millimeters of water per day)] was determined by weighing the PVC tubes containing well-watered turfgrass every 3 days to determine water loss on a daily basis as ETo. Deficit irrigation treatments were applied as follows: well-watered control, mild drought stress (60% ETo), and severe drought stress (20% ETo). Leaf water content was lower at 6, 12, and 20 days of treatment for the 20% ETo treatment and 20 days after treatment began for the 60% ETo treatment. Compared with the well-watered control, ψS was lower in the 60% ETo treatment on all three measurement dates. Sucrose was higher at 8 and 14 days after treatment began in the 60% ETo treatment and on all three measurement dates in the 20% ETo treatment relative to the well-watered control. No difference in sucrose level was observed between the 20% ETo and 60% ETo irrigation regimes at 8 and 14 days of treatment. Beginning 14 days after treatment, tall fescue had a higher level of SPS in the 60% ETo and 20% ETo treatments compared with the well-watered treatment. Tall fescue receiving 60% or 20% ETo had a lower level of AI activity on all measurement dates. Results suggest that the decrease in ψS was accompanied by higher sucrose levels, which were the result of the increased level of SPS and SS activity and a decline in AI activity.

scholarly journals Evaluation of Resistance of Winter Wheat to Fusarium acuminatum by Inoculation of Seedling Roots with Single, Germinated Macroconidia

Plant Disease ◽  
1998 ◽  
Vol 82 (3) ◽  
pp. 300-302 ◽  
Author(s):  
M. Mergoum ◽  
J. P. Hill ◽  
J. S. Quick
Keyword(s):  
Water Stress ◽  
Winter Wheat ◽  
Water Content ◽  
Root Rot ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Ion Leakage ◽  
Wheat Cultivars ◽  
Fusarium Acuminatum ◽  
Seedling Roots

Fusarium acuminatum is one of the causal agents of dryland root rot of winter wheat in Colorado. The effect of F. acuminatum seedling root infection, recorded at heading, on winter wheat cultivars Sandy and CO84 was investigated in the greenhouse. Winter wheat seeds were surface disinfested, germinated, and vernalized. Vernalized seedling roots were inoculated by placing a single, germinated macroconidium of F. acuminatum on the largest root. Inoculated and non-inoculated vernalized seedlings were transplanted to pots and half the plants subjected to water stress. Inoculated plants had significantly lower survival rates and, at maturity, lower relative leaf water content, fewer tillers, shorter plant height, and higher cell ion leakage than non-inoculated plants. Wheat cultivars differed significantly for most traits studied. CO84 was susceptible whereas Sandy was more tolerant of the pathogen, particularly under water stress conditions. These results suggest that relative leaf water content, cell ion leakage, and to some extent seedling survival may be useful attributes for evaluation of resistance to the root rot pathogen.

scholarly journals Critical Leaf Water Content for Maize Photosynthesis under Drought Stress and Its Response to Rewatering

2021 ◽  
Vol 13 (13) ◽  
pp. 7218
Author(s):  
Xingyang Song ◽  
Guangsheng Zhou ◽  
Qijin He
Keyword(s):  
Drought Stress ◽  
Water Content ◽  
Global Climate ◽  
Leaf Water ◽  
Extreme Weather Events ◽  
Leaf Water Content ◽  
Growth Stages ◽  
Stomatal Limitation ◽  
Jointing Stage ◽  
Maize Photosynthesis

Crop photosynthesis is closely related to leaf water content (LWC), and clarifying the LWC conditions at critical points in crop photosynthesis has great theoretical and practical value for accurately monitoring drought and providing early drought warnings. This experiment was conducted to study the response of LWC to drought and rewatering and to determine the LWC at which maize photosynthesis reaches a maximum and minimum and thus changes from a state of stomatal limitation (SL) to non-stomatal limitation (NSL). The effects of rehydration were different after different levels of drought stress intensity at different growth stages, and the maize LWC recovered after rewatering following different drought stresses at the jointing stage; however, the maize LWC recovered more slowly after rewatering following 43 days and 36 days of drought stress at the tasselling and silking stages, respectively. The LWC when maize photosynthesis changed from SL to NSL was 75.4% ± 0.38%, implying that the maize became rehydrated under physiologically impaired conditions. The LWCs at which the maize Vcmax25 reached maximum values and zero differed between the drought and rewatering periods. After exposure to drought stress, the maize exhibited enhanced drought stress tolerance, an obviously reduced suitable water range, and significantly weakened photosynthetic capacity. These results provide profound insight into the turning points in maize photosynthesis and their responses to drought and rewatering. They may also help to improve crop water management, which will be useful in coping with the increased frequency of drought and extreme weather events expected under global climate change.

scholarly journals Isotopic and Water Relation Responses to Ozone and Water Stress in Seedlings of Three Oak Species with Different Adaptation Strategies

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 864
Author(s):  
Claudia Cocozza ◽  
Elena Paoletti ◽  
Tanja Mrak ◽  
Saša Zavadlav ◽  
Tom Levanič ◽  
...  
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Content ◽  
Leaf Gas Exchange ◽  
Water Relation ◽  
Adaptation Strategies ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Global Changes ◽  
The Impact

The impact of global changes on forest ecosystem processes is based on the species-specific responses of trees to the combined effect of multiple stressors and the capacity of each species to acclimate and cope with the environment modification. Combined environmental constraints can severely affect plant and ecological processes involved in plant functionality. This study provides novel insights into the impact of a simultaneous pairing of abiotic stresses (i.e., water and ozone (O3) stress) on the responses of oak species. Water stress (using 40 and 100% of soil water content at field capacity—WS and WW treatments, respectively) and O3 exposure (1.0, 1.2, and 1.4 times the ambient concentration—AA, 1.2AA, and 1.4AA, respectively) were carried out on Quercus robur L., Quercus ilex L., and Quercus pubescens Willd. seedlings, to study physiological traits (1. isotope signature [δ13C, δ18O and δ15N], 2. water relation [leaf water potential, leaf water content], 3. leaf gas exchange [light-saturated net photosynthesis, Asat, and stomatal conductance, gs]) for adaptation strategies in a Free-Air Controlled Exposure (FACE) experiment. Ozone decreased Asat in Q. robur and Q. pubescens while water stress decreased it in all three oak species. Ozone did not affect δ13C, whereas δ18O was influenced by O3 especially in Q. robur. This may reflect a reduction of gs with the concomitant reduction in photosynthetic capacity. However, the effect of elevated O3 on leaf gas exchange as indicated by the combined analysis of stable isotopes was much lower than that of water stress. Water stress was detectable by δ13C and by δ18O in all three oak species, while δ15N did not define plant response to stress conditions in any species. The δ13C signal was correlated to leaf water content (LWC) in Q. robur and Q. ilex, showing isohydric and anisohydric strategy, respectively, at increasing stress intensity (low value of LWC). No interactive effect of water stress and O3 exposure on the isotopic responses was found, suggesting no cross-protection on seasonal carbon assimilation independently on the species adaptation strategy.

scholarly journals Respons tanaman kelapa sawit (Elaeis guineensis Jacq) terhadap cekaman kekeringan Respons of oil palm (Elaeis guineensis Jacq) to water stress

2016 ◽  
Vol 69 (2) ◽  
Author(s):  
Nurita TORUAN-MATHIUS ◽  
Gede WIJANA ◽  
Edi GUHARJA ◽  
Hajrial ASWIDINNOOR ◽  
Sudirman YAHYA ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Oil Palm ◽  
Glycine Betaine ◽  
Elaeis Guineensis ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Sds Page ◽  
Aba Content

SummaryWater stress affect many physiological andbiochemical processes of oil palm. A series ofexperiments were conducted to characterize thewater stress-induced changes in physiologicalrespons of oil palm to water stress, in glass housecondition. The experiment consisted of (1)permanent leaf wilting point measured based onsoil water content, leaf water content, specificleaf area and leaf water potential . Plants wereconducted by termination of watering to theplants, and control plants were maintained wellwatered during 0,3,6,9,12,15,18 and 21 days ofMK356 and MK365 clones. Experiment (2)effect of water stress on changes of leaf waterpotential, protein bands pattern, proline,glycine-betaine, osmotical sugar, and abcisicacid (ABA) of MK356 and MK365 clones.Water stress was induced by termination ofwatering to the plants and maintained wellwatered during 0, 7,14, and 18 days.Experiment (3) changes of protein bands patternby total protein and electrophoresis SDS-PAGEand SDS-PAGE 2D protein. of H2(D10DxD8D)x(L9TxL2T); H12 (D8D Self) x(L9T x L2T). H3 and H9 (BJ028D x BJ2117P)hybrids. H2 and H12, H3 and H9 potentiallytolerant and untolerant to water stress,respectively. The results showed that permanentwilting point reached in 18 days of water stress.Water stress caused the decreased soil watercontent, leaf water potential, leaf water content,relative leaf water content , and relative leafarea of two clones. Water potential, leaf watecontent dan relative leaf water content ofMK365 decrease faster compare with MK356.Soil water content sharply decrease after 6 hoursand in 18 days of water stress leaf waterpotential value < - 2.55 Mpa. Proline, glycine-betaine and glucose content were affect by waterstress. Interaction among water stress and cloneswere significantly appear in stachiose content.Leaf water potential values decrease, whereasproline, ABA and glycine-betaine contentsincrease during water stress especially inMK356. Generally showed that ABA content inMK356 higher than MK 365. The differencesresponses of MK356 with MK 365 obtained fromprolin,xylose and ABA content. Induction of newprotein pI 4.7-36 kDa, pI5.3-34 kDa, pI 4.6-32kDa and pI 5.3-36 kDa obtained from hybridspotentially tolerant to water strees, none inuntolerant hybrids.RingkasanCekaman kekeringan mempengaruhiproses fisiologis dan biokimia tanaman kelapasawit. Serangkaian percobaan bertujuan untukmengkarakterisasi perubahan fisiologis tanamankelapa sawit terhadap cekaman kekeringan,dalam kondisi rumah kaca telah dilakukan.Percobaan terdiri atas (1) penetapan titik layupermanen, berdasarkan perubahan potensial airdaun, kadar air daun, kadar air daun relatif, danluas daun relatif dengan perlakuan tanpa dandengan penyiraman selama 0, 3, 6, 9, 12, 15, 18dan 21 hari. Percobaan (2) penetapan perubahankadar prolin, glisin-betain, gula-gula osmotikaldan asam absisik (ABA), terhadap cekamankekeringan. Perlakuan adalah tanpa dan denganpenyiraman selama 0, 7, 14, dan 18 hari.Percobaan (3) analisis perubahan pola pita proteindaun hibrida H2 (D10DxD8D)x(L9TxL2T); H12(D8D Self) x (L9T x L2T). H3 dan H9 (BJ028Dx BJ2117P) terhadap cekaman kekeringan dengantotal protein, dan pola pita protein dengan SDSPAGE dan SDS-PAGE 2D. H2 dan H12 serta H3dan H9 masing-masing berpotensi toleran danpeka terhadap cekaman kekeringan. Hasil yangdiperoleh menunjukkan bahwa titik layupermanen dicapai pada hari ke 18 setelah dibericekaman kekeringan. Cekaman kekeringanmenurunkan kadar air tanah media tumbuh,potensial air daun, kadar air daun, kadar air daunrelatif, dan luas daun relatif untuk kedua klon.Potensial air daun, kadar air daun dan kadar airdaun relatif klon MK365 menurun lebih cepatdibandingkan dengan klon MK356. Kadar airtanah menurun tajam setelah 6 hari dibericekaman air dan potensial air daun mencapai<-2.55 MPa pada 18 hari setelah diberi cekaman.Cekaman kekeringan nyata berpengaruh terhadapkadar prolin, glisin betain dan glukosa. Interaksiantar lama cekaman kekeringan dan perbedaanklon diperoleh pada perubahan gula stahiosa.Tampak bahwa semakin menurun nilai potensialair daun menyebabkan kadar prolin semakinmeningkat. Hal yang sebaliknya terjadi terhadapkadar glisin-betain yang mengalami penurunanterutama untuk klon MK356. Kadar ABAMK356 dan MK365 meningkat sejalan dengansemakin lama diberi cekaman. Secara umumtampak bahwa kadar ABA pada MK356 lebihtinggi dibandingkan dengan MK 365. Perbedaanrespons klon MK356 dengan MK 365 terjadipada kadar prolin, gula silosa dan ABA.Hibridaberpotensi toleran memberikan respon terhadapcekaman kekeringan dengan menginduksi proteinbaru pI 4,7-36 kDa, pI5,3-34 kDa, pI 4,6-32 kDadan pI 5,3- 36 kDa, sedangkan pada hibridayang berpotensi peka protein tersebut tidakditemukan

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