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1.
Field studies were conducted during the winter seasons of 1995–96 and 1996–97 at the Agricultural Farm of Aligarh Muslim University, Aligarh, India on mustard ( Brassica juncea L. Czern & Coss., var. Alankar) under non-irrigated conditions, to evaluate the effect of foliar spray of 200 p.p.m. ethrel (2-chloroethyl phosphonic acid) at flowering growth stage along with basal 0, 40, 80 or 120 kg N ha−1 on net photosynthetic rate (PN), stomatal conductance (CS), stomatal resistance (RS), leaf K content, relative water content (RWC), leaf area index (LAI) and total dry matter (TDM) production monitored at 20 days after spray application, and plant N content, seed N content, nitrogen harvest index (NHI), nitrogen yield merit (NYM), pods plant−1, 1000 seed weight, seed yield, biological yield, harvest index (HI), seed yield merit (SYM) and merit of genotype (MOG) at harvest. Results indicated that, at 0 or 40 kg N ha−1, ethrel did not produce any significance effect, but at basal 80 kg N ha−1, ethrel affected the parameters favourably with the exception of 1000 seed weight, HI, seed N and NHI. Ethrel-sprayed plants utilized N from the soil more effectively and showed increased NYM. Yield attributes, seed yield and merit of genotype (in terms of NYM and SYM) were also enhanced. Ethrel spray enhanced seed yield under water stress conditions mainly by increasing K uptake and retaining higher RWC, thereby decreasing RS and increasing LAI, PN and TDM production.  相似文献   

2.
Water use efficiencies for the whole plant (WUE1) and single leaves (WUE1) were studied in a greenhouse as a function of soil moisture during four phenological stages of bush bean growth. WUE1 increased significantly with soil moisture stress and attained its maximum value before the flowering stage. WUE1 and WUE1 were linearly related ( r = 0.92), and WUE1 was correlated with the transpiration rate ( r = -0.87), stomatal conductance ( r = -0.80) and photosynthetic rate ( r = 0.81). Carbon isotope discrimination.), decreased as soil moisture decreased, and) was negatively correlated with both WUE1 ( r = -0.92) and WUE1 ( r = -0.88). There were significant differences in leaf N among water regimes.  相似文献   

3.
In rape (Brassica napus L., cv. Global) seed growth mainly depends on husk CO2 assimilation. In irrigated plants, the net photosynthetic rate (Amax) was 10–13 μmol CO2 m−2 s−1 in non-maturing pods and correlated with nitrogen content. The stomatal conductance of water vapour (gH2O) was 0.3 mol m−2 s−1 in non-maturing pods. The photosynthetic nitrogen use efficiency (NUE) was 8.3 μmol CO2g−1 N s−1, about one-third of that in leaves. The photosynthetic water use efficiency (WUE; AmaxgH2O−1) was similar in pods and leaves. In severely droughted plants, the photosynthetic rate was reduced to 38%. The seed growth rate, however, was not influenced by intermittent periods of water stress, indicating translocation of assimilates to the seeds. The drought resistant character of the pods was due to low specific area, succulence, low stomatal conductance causing a small decrease of ΔΨ day−1 during soil drying and maintenance of high relative water content during severe drought. A mathematical formulation of the pod water release curve was undertaken. © (1997) Elsevier Science B.V.  相似文献   

4.
Quinoa (ChenopodiumquinoaWilld.) is a highly nutritious Andean seed crop which shows great potential to grow under a range of hostile environments. The objective of this study was to investigate the differences of drought tolerance of a Bolivian (Achachino) and a Danish (Titicaca) variety, and especially drought‐related adaption strategies. Soil water status was expressed as the fraction of transpirable soil water (FTSW). Relative stomatal conductance (RSC), relative transpiration (RT) and relative leaf water potential (RLW) were calculated by determining stomatal conductance, transpiration rate and leaf water potential of the drought‐treated plants relative to those of fully irrigated plants. The responses of RSC, RT and RLW to decreasing FTSW were described by a linear‐plateau model. The critical value of FTSW was the threshold of FTSW where the parameters studied decreased. The thresholds increased CS for stomatal conductance, CT for transpiration and CLfor leaf water potential. Achachino showed significantly lower CT and CL when compared with Titicaca, implying that transpiration and leaf water potential were less affected under mild drought conditions in the Bolivian variety. CS in Achachino was significantly higher than CL and CT, which indicated that stomatal conductance declined before transpiration and leaf water potential were reduced. Such difference was found in Titicaca where reduction of leaf area had more effect on transpiration than stomatal closure. Slower growth rate and smaller leaf area in combination with a lower stomatal conductance was found to contribute to drought resistance in Achachino. ABA concentration in the xylem sap tended to increase in both varieties after 2 days onset of drought, prior to decline in leaf water potential. Titicaca showed significantly (P < 0.05) higher ABA concentration when compared with Achachino under both fully irrigated and drought conditions. Titicaca had higher xylem nutrient concentration in comparison with Achachino in both fully‐watered and drought plants at day 2 after onset of soil drying. It was concluded that Titicaca was more sensitive to progressive drought than Achachino which avoided water loss by means of lower growth rate and smaller leaf area.  相似文献   

5.
The effects of exposure in the vegetative phase of growth to 5- or 10-day spells of soil drought (30% field water capacity) on assimilation, dissimilation and accumulation of 14C and on dry matter growth were studied in two maize hybrids, nos. 8344 and 8388 (Garst Seed Co.) of high and low drought tolerance. Under control water regime in soil there was no difference in 14CO2 uptake and dry matter growth between hybrids. After five days of drought 14CO2 assimilation dropped by about 75% referred to unit weight of dry matter in hybrid 8344 and by 56% in hybrid 8388. After 10 days of drought 14CO2 assimilation rate was reduced by 75% in both hybrids. Soil drought increased the 14C dissimilation. There were no significant differences between hybrids in all treatments, with the exception of 5 days drought; after this treatment the dissimilation rate of hybrid 8344 was higher than that of 8388. Changes of translocation of 14C and its accumulation in particular organs occurred in drought treated plants; the amount of 14C accumulated in roots of plants of hybrid 8344 increased, while that of hybrid 8388 decreased. Changes of 14C accumulation in roots were positively correlated to changes of dry matter of those organs. One day after 10 days of drought assimilation and dissimilation rates in both hybrids were about 60% of controls.  相似文献   

6.
Peanut stands often face water deficits in the tropics and subtropics, especially in drought-prone areas of India. The effect of drought on peanut production has previously been studied. However, there is a lack of information on the post-stress recovery mechanism. The objective of this study was to investigate the recovery mechanism after relief of water stress. The effect of short-term drought applied (for 12 days) at the pre-flowering, peak flowering and pod-filling stages on chlorophyll (Chl) pigments, water use efficiency (Wue), quantum yield (Qy), root/shoot ratio (R:S), relative growth rate (RGR), net assimilation rate (NAR) and flower production during stress and subsequent post-stress recovery was examined. The leaf water potential (ψleaf) and leaf relative water content (RWC) in plants subjected to water deficit were reduced to 1/10 and 2/3, respectively, of the corresponding control values. Moisture deficit significantly reduced Chl a and b concentrations, the Chl a/b ratio, stomatal conductance, photosynthesis, Wue and Qy. However, a strong recovery of these traits was noted after rewatering, which led to onset of fresh growth on post-stress, with a marked increase in RGR and NAR and a flush of flowering. Drought significantly enhanced R:S, which accelerated post-stress recovery. Peanut stands exhibited excellent ecophysiological recovery with the post-stress onset of fresh growth. This strong recovery mechanism found in peanut stands suggests that peanut has high environmental plasticity.  相似文献   

7.
《棉花学报》2018,30(2):155-163
[Objective] The purpose of this study was to examine potential drought tolerance mechanisms in cotton (Gossypium hirsutum L.). Biochemical (antioxidant, protein and compatible osmolyte) and physiological (photosynthesis) responses to drought stress during the flowering and fruiting stages were examined. [Method] Using two cotton genotypes (A001 and A705) with different drought tolerance, a pot study was conducted in 2016 with treatments consisting of control (well-watered) and water stress. Water stress treatment was designed as withholding water from the pots until stomatal closure followed by limited water supply for 25 days where water-stressed plants received 40% of the optimum quantity of water. Measurements were made on soluble protein, proline and malonaldehyde (MDA) concentrations, peroxidase (POD) activity and photosynthetic characteristics (net photosynthetic rate Pn, transpiration rate E, stomatal conductance Gs) during the period of water stress. [Result] The soluble protein concentration was decreased and POD activity and MDA level were increased in the leaf subtending cotton boll of A001 under water deficit when compared with the control, but no response was observed in A705. Proline level responded to water deficit inconsistently between the two genotypes and across all sampling dates. Water stress significantly decreased Pn, E and Gs in the main stem leaves for both A001 and A705. [Conclusion] The results indicated that POD, soluble protein and MDA are involved in A001 and A705 responses to water deficit, and A705 is more tolerant to soil drought than A001.  相似文献   

8.
This study investigated whether the exogenous application of glycine betaine (GB) could alleviate the adverse effects of water deficit on sunflower. Two sunflower lines, Gulshan-98 and Suncross, were subjected to water deficit at the vegetative or the reproductive stages of plant growth. Three levels (0, 50 and 100 mmol l−1) of GB were applied as a pre-sowing seed treatment or as a foliar spray at the time of initiation of water deficit at the vegetative or reproductive stages. Foliar application of GB at the time of initiation of water deficit treatments showed a marginal increase in shoot biomass in drought-stressed plants. Exogenously supplied GB as a foliar spray also showed a positive role in reducing the effects of water deficit on net CO2 assimilation rate, transpiration rate and sub-stomatal CO2 concentration in both sunflower lines. Pre-sowing seed treatment with GB had no effects on the above-mentioned physiological and growth attributes in both normally irrigated and drought-stressed plants. Taken together, foliar application of GB increased net CO2 assimilation rate which in turn showed a slight increase in growth of water-stressed plants but this increase was not related to stomatal regulation.  相似文献   

9.
为检验增施CO2对马铃薯组培苗植株光合特性及微型薯产量的影响,选用马铃薯品种夏坡蒂组培苗为试验材料,于2015年在温室条件下进行了两批次试验。结果表明,增加CO2浓度可显著增加植株的叶面积、叶片净光合速率和胞间CO2浓度,且CO2 750μmol/mol处理>550μmol/mol处理>CK（空气）,但增加CO2浓度降低了马铃薯植株叶片气孔导度和蒸腾速率。结果还表明,增施CO2增加了马铃薯单株结薯数、单个薯重和单株产量,其增幅随CO2量的增加而增加。上述结果充分证明在温室条件下增施CO2对加速马铃薯微型薯的繁育有积极作用。  相似文献   

10.
An attempt has been made to study the interactive effect of elevated CO2 and moisture stress on photosynthesis, growth and water relations of Brassica species using open top chambers. It was observed that plants responded to elevated CO2 significantly under moisture stress condition mitigating the adverse effects on photosynthesis and growth of Brassica species. Relatively drought susceptible species, viz. B. campestris and B. nigra , responded to elevated CC2 markedly as compared to less sensitive B. carinata and B. juncea plants. The water status of plants significantly improved under elevated CO2 concentration possibly by increasing stomatal resistance and/or by increased root growth.  相似文献   

11.
A versatile method was developed for the application of 1000 ppm CO2 during the whole growth period of plants. Temperature controlled water cooling and ventilation of the greenhouse resulted in a monthly CO2 enrichment time of 60 to 90 % of the total light period. Digitalis lanata , grown in greenhouses with CO2 enrichment during the whole growth phase from April to November, produced twice as much biomass as field cultivated plants.
The relative yield of the glycoside digoxin per gram Digitalis drug dry weight was 0.4% in field grown and 0.7% in greenhouse cultivated plants. The production of digoxin per hectare in the greenhouse at 1000 ppm CO2 was almost 3.5-fold that by field cultivation. Drug yield and secondary metabolite production in D. lanata were remarkably influenced by increased temperature and elevated CO2 partial pressure in the greenhouse.  相似文献   

12.
The physiological effects of elevated CO2 and/or O3 on Solanum tuberosum cv. Bintje were examined in Open-Top Chambers during 1998 and 1999 at experimental sites across Europe as part of the EU ‘Changing Climate and Potential Impacts on Potato Yield and Quality’ programme (CHIP). At tuber initiation (≈20 days after emergence, DAE) elevated CO2 (680 μl l−1) induced a 40% increase in the light saturated photosynthetic rate (Asat) of fully expanded leaves in the upper canopy. This was 16% less than expected from short-term exposures of plants grown under ambient CO2 (360 μl l−1) to elevated CO2, indicating that photosynthetic acclimation began at an early stage of crop growth. This effect resulted from a combination of a 12% reduction in stomatal conductance (gs) and a decline in photosynthetic capacity, as indicated by the significant reductions in the maximum carboxylation rate of Rubisco (Vcmax) and light-saturated rate of electron transport (Jmax) under elevated CO2. The seasonal decline in the promotion of photosynthesis by elevated CO2 reflected the concurrent decrease in gs. Vcmax and Jmax were both reduced in plants grown under elevated CO2 until shortly after maximum leaf area (MLA) was attained. Although non-photorespiratory mitochondrial respiration in the light (Rd) increased during the later stages of the season, net photosynthesis was consistently increased by elevated CO2 during the main part of the season. Photosynthetic rate declined more rapidly in response to elevated O3 under ambient CO2, and the detrimental impact of O3 was most obvious after MLA was attained (DAE 40–50). Several exposure indices were compared, with the objective of determining the critical ozone level required to induce physiological effects. The critical O3 exposure above which a 5% reduction in light saturated photosynthetic rate may be expected (expressed in terms of cumulative exposure above 0 nl l−1 O3 between emergence and specific dates during the season (AOT0-cum)) was 11 μl l−1 h; however this value should only be extrapolated beyond the CHIP dataset with caution. The interaction between O3 and stomatal behaviour was more complex, as it was influenced by both long-term and daily exposure levels. Elevated CO2 counteracted the adverse effect of O3 on photosynthesis, perhaps because the observed reduction in stomatal conductance decreased O3 fluxes into the leaves. The results are discussed in the context of nitrogen deficiency, carbohydrate accumulation and yield.  相似文献   

13.
为探明适合贵州地区种植薏苡的栽培技术,以薏苡14-2为材料,采用裂区试验设计,研究硫酸钾复合肥和种植密度对薏苡产量、农艺性状及光合特性的影响。结果表明,施肥量和种植密度对产量、株高、主茎节数、穗粒数、千粒重、净光合速率、气孔导度、胞间CO2浓度和蒸腾速率均有极显著影响;随着施肥量和种植密度的增加,产量、株高、主茎节数、穗粒数、千粒重、净光合速率、气孔导度和蒸腾速率均表现为先增加后降低,而胞间CO2浓度表现为先降低后增加。相关分析表明,产量与株高、主茎节数、穗粒数、千粒重、净光合速率、气孔导度和蒸腾速率均呈极显著正相关,而与胞间CO2浓度呈极显著负相关。在贵州地区种植薏苡时,以施肥量为225kg/hm 2、种植密度为12万株/hm 2较好。  相似文献   

14.
Measurements of stomatal conductance on field-grown potato (Solanum tuberosum L.) cv. Bintje from the CHIP programme were combined to study the response to environmental factors. 3274 data points were used. Data were obtained from five sites: Jokioinen in Finland, Östad in Sweden, Giessen in Germany, Tervuren in Belgium and Sutton Bonnington in UK. Measurements were made in open-top chamber treatments with ozone and carbon dioxide exposure and in the ambient air. A typical light response curve was obtained with light saturation at approximately 400 μmol m−2 s−1 photosynthetically active radiation (PAR). The leaf temperature optimum for stomatal conductance was 29 °C. The stomatal conductance declined strongly at leaf-to-air vapour pressure differences >20 hPa. An elevated carbon dioxide concentration (680 μl l−1) reduced the stomatal conductance by up to approximately 20%. Elevated ozone reduced the stomatal conductance towards the end of the growth period, in addition to the negative effect by ordinary senescence on stomatal conductance. A multiplicative model, based on the boundary line technique, was used to estimate the relationship between stomatal conductance and the environmental variables. Test with the data sets from two sites providing sufficient data, Östad and Giessen, showed that the multiplicative model had R2-values of 0.60 and 0.42, respectively, for the relationship between calculated and observed conductance. Test of the model with an independent data set from an open-top chamber experiment with the potato cultivar Kardal showed an R2 of 0.59 between calculated and observed conductance. The conductance model was used to estimate the accumulated ozone uptake (CUO3) by potato leaves from emergence to harvest. The relationship between CUO3 and relative yield loss, using a threshold for the ozone uptake rate of 7 nmol m−2 s−1, provided a higher R2-value (0.45) than CUO3 without any threshold and relationships based on the accumulated exposure over 40 nmol mol−1 (AOT40) or the sum of all hourly average ozone concentrations exceeding 60 nmol mol−1 (SUM06). All four relationships were however statistically significant.  相似文献   

15.
I. Molnár    G. Linc    S. Dulai    E. D. Nagy    M. Molnár-Láng 《Plant Breeding》2007,126(4):369-374
A spontaneously developed wheat–barley 4H(4D) disomic substitution line was identified cytogenetically using genomic in situ hybridization (GISH), multicolour fluorescent in situ hybridization (FISH) and microsatellite markers. The ability of the barley 4H chromosome to compensate for wheat 4D in response to mild drought stress was also investigated. In the barley cv. 'Betzes' and the 4H(4D) substitution line, mild osmotic stress induced intensive stomatal closure, resulting in reduced water loss through transpiration and unchanged relative water content in the leaves. As the CO2 assimilation rate remained relatively high, the water use efficiency, which is an important factor associated with drought tolerance, increased extensively under mild osmotic stress in these lines. In the case of the parental wheat genotypes, however, mild drought stress induced less intense stomatal closure and a greater decrease in the CO2 assimilation rate than in barley or in the substitution line, resulting in unaugmented or reduced water use efficiency. The results demonstrate that genes localised on the 4H chromosome of barley were able to increase the water use efficiency of the wheat substitution line, which is suitable for improving wheat drought tolerance through intergeneric crossing.  相似文献   

16.
Differences in gas exchange parameters i.e. carbon exchange rate (CER), transpiration (Tr), water vapor conductance (g) were investigated, under a controlled environment, in a semi-dwarf (SD) Triticum aestivum line, its tall (TL) near isoline and the Payne (PA) variety characterized by small leaves. The plants were maintained in: (a) optimal substrate moisture condition (CTR); (b) salinized by watering with a 0.12 m NaCl solution (SLT); (c) water stressed by withholding waterings during a period of six days (STR); (d) stressed and salinized during the same period and with the same saline solution (S + S). CER and Tr were negatively affected by the stresses; SLT and S + S treatments had a higher WUE compared to their respective controls CTR and STR.
SD line had a better performance in terms of CER and WUE, particularly when water and salt stresses interacted. Leaf anatomy and assimilation/internal CO2 concentration curves contributed to explaining the SD performance.  相似文献   

17.
探究在干旱胁迫和复水过程中白姜花光合和叶绿素荧光的生理响应,为姜花属植物抗旱性研究提供参考依据。以当年生白姜花单株盆栽苗为材料进行自然干旱试验,分别于干旱的第0、3、6、9、12天和复水第3天测量土壤相对湿度、叶片枯萎率、光合和叶绿素荧光参数。在干旱的第3、6、9、12天,土壤相对湿度从第0天的84.60%分别下降到了59.20%、34.40%、20.40%、15.40%;随着干旱程度的不断加深,叶片枯萎率、蒸腾速率、净光合速率、气孔导度、胞间CO2浓度、最大光化学效率、实际光能转化效率、光化学淬灭系数和光合电子传递速率均呈现下降趋势,其胁迫时期的参数间均存在显著差异(P<0.05);而水分利用效率、气孔限制值、非光化学淬灭系数则呈现上升趋势,其胁迫时期的参数间也存在显著差异(P<0.05);复水3天后各项指标均有不同程度恢复。综合分析各项参数,干旱胁迫对白姜花光合和荧光特性影响显著,气孔因素是导致白姜花净光合速率下降的主要因素;干旱后复水各项指标均能恢复,表明白姜花具有一定的干旱适应能力。  相似文献   

18.
渍水和高温是长江中下游地区棉花生育中后期的主要气象灾害。2011和2012年在桶栽栽培条件下,研究了棉花花铃期功能叶光合特性、膜脂过氧化代谢对渍水(土表积水2~3 cm,7 d)、高温(7 d,每天持续6 h)及其复合胁迫的响应差异及其与产量的关系。结果表明,渍水、高温单独处理均增加了棉花主茎倒4叶超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化物酶(Peroxidase,POD)活性和丙二醛(Malonaldehyde,MDA)含量。渍水和高温共同处理导致SOD活性降低,POD活性迅速增强和MDA含量急剧增加。渍水、高温及渍水+高温均降低了叶片SPAD值、光系统II最大光化学量子产量(Maximal photochemical quantum yield of photosystem II,F_v/F_m)和潜在光化学活性(Potential photochemical activity of photosystem II,F_v/F_0);同时降低了叶片净光合速率(Net photosynthesis rate,P_n)、气孔导度(Stomatal conductance,C_s)和蒸腾速率(Transpiration rate,T_r),增加了胞间二氧化碳浓度(Intercellular CO2concentration,C_i);减少了单株成铃数,降低了铃重,进而降低了籽棉产量,而对衣分影响不明显。从产量受害程度来看,渍水+高温(23.0%)渍水(17.1%)高温(9.8%)。除Ci外,SPAD值(叶绿素含量)、P_n、T_r、C_s、F_v/F_m及F_v/F_0与产量均呈显著正相关关系,其中SPAD值与产量的相关性最好。可将功能叶SPAD值作为作物响应逆境胁迫的敏感指标,应用到棉花抗逆能力评价和气象灾害减产评估之中。  相似文献   

19.
Field bean planes cultivar Nadwiślański were submitted to soil drought (30 % of field soil water capacity) for 5 days at the stage of pod formation (A) and of rapid pod growth (B) and then exposed for 20 minutes to 14CO2. Radioactivity of leaves, stems, roots, and pods or pod shells and seeds was measured 1, 5, 24 and 48 hours after exposition.
In both stages soil drought reduced by about five times total CO2 assimilation, mainly owing to lower activity of the photosynthetic apparatus and also, though less so, to reduced leaf growth. Photosynthetic activity referred to the dry weight of the leaves dropped to 22-35% of controls. Accumulation of photosynthetates in generative organs was much less depressed than 14CO2 assimilation. 48 hours after exposition to 14CO2 of drought treated plants, the contents of 14C of pods in phase A, and seeds in phase B, amounted to respectively 24% and 36% of assimilated 14C and equalled 91.5% and 74% of the corresponding values for controls.
The progressive decline of radioactivity in leaves and stems after 14CO2 exposition was distinctly correlated to the rise of radioactivity of generative organs both in soil drought treated plants and in controls. Slightly lower values of correlation coefficients in drought treated plants may indicate impairment under drought conditions of synchronization in processes of unloading and accumulation of assimilates.
In plants drought treated in phase A the ability to dissimilate 14C was reduced to about 59% of that in controls, but when drought was applied in phase B, dissimilation rate was about three times as high.  相似文献   

20.
Development of hybrids between white clover ( Trifolium repens L.) and Trifolium nigrescens provides a novel route for genetically improving the reproductive capacity of white clover, provided the hybrids are agronomically viable, particularly with respect to N2 fixation. A comparative study of growth and rates of N2 fixation over 21 days was conducted with the parental species, F 1 hybrids and backcross hybrids, in flowing solution culture, without a supply of mineral N to the plants. T. nigrescens was unable to fix N2 in association with the strains of Rhizobium leguminosarum biovar. trifolii selected for inoculation. Rates of N2 fixation per plant increased in the order T. nigrescens < F 1 hybrid < T. repens < backcross 1. Specific rates of N2 fixation (days 0–21) increased in the order T. nigrescens < F 1 hybrid < backcross 1 <  T. repens . Dry matter production and nodule biomass per plant increased at a higher rate in backcross 1 hybrids than in T. repens. The results suggest that the potential for N2 fixation by backcross 1 hybrids is at least as great as that by T. repens .  相似文献   

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