氮磷水平与气象条件对春小麦籽粒蛋白质含量形成动态的影响

以3个品质类型春小麦品种的施肥和播期试验为基础,通过建立籽粒蛋白质含量形成动态的拟合方程,定量揭示籽粒蛋白质含量形成动态及氮磷肥与气象条件的影响效应。结果表明,灌浆期籽粒蛋白质含量随时间动态变化的普遍规律符合一元三次多项式曲线,即呈自开花始先降低后升高的单谷曲线变化。氮磷肥与气象条件的影响及基因型差异通过方程特征量而体现。氮水平增加,高蛋白品种蛋白质含量增加,动态曲线谷值和峰值均明显提高且出现时间分别提前和推后。磷水平增加,高蛋白强筋品种蛋白质含量降低,高蛋白中筋品种则增加;高蛋白品种谷值和峰值均提高且出现时间推迟。低蛋白品种蛋白质含量随氮磷肥变化不明显且幅度很小。在没有水分胁迫的情况下,光温互作是影响籽粒蛋白质含量动态形成的首要因子,其次为降水;而气温日较差则为最敏感因子。较高光温条件互作前提下,增加灌浆期温度日较差使高蛋白品种蛋白质含量提高,低蛋白品种则降低。高蛋白相比于低蛋白品种更易受氮磷水平和气象条件影响。     

Influence of soil applications of nitrogen on nitrate reductase activity,leaf and grain protein content in sorghum

Summary Three sorghum genotypes, L.187, SK5912 and RCFA×L.187 (the latter being a hybrid) were field grown under four nitrogen application rates and replicated four times. The experiments were of complete randomized plot design and conducted in 1976, 1977 and 1978.Nitrate Reductase Activity (NRA) was measured at 5, 7, 9, 11, 13, and 15 weeks and at 18, 19, 20 and 21 weeks after planting in 4th vegetative leaf and flag leaf respectively. Flag leaf, 4th leaf and grain protein contents were also measured.Nitrogen application generally increased NRA in both 4th leaf and flag leaf in the 3 genotypes at all the sampling dates.NRA of the hybrid, RCFA×L.187 was consistently higher than those of SK5912 and L.187 (both straight varieties).NRA of 4th leaf was negatively correlated with leaf protein but flag leaf protein tended to increase with applied nitrogen.Flag leaf NRA was positively and significantly correlated with grain protein indicating an important part played by the flag leaf relative to protein accumulation of the developing grain.     

A microsatellite marker associated with a QTL for grain protein content on chromosome arm 2DL of bread wheat

 This study was undertaken with a view to tag gene(s) controlling grain protein content (GPC) using molecular markers in bread wheat. For this purpose, the genotype PH132 with high protein content (13.5%) was crossed with genotype WL711 with significantly lower protein content (9.7%), and 100 RILs were derived. These RILs showed normal distribution for protein content. The parental genotypes were analysed with 232 STMS primer pairs for detection of polymorphism. Of these, 167 primer pairs gave scorable amplification products, and 57 detected polymorphism between the parents. Using each of these 57 primer pairs, we carried out bulked segregant analysis on RILs representing the two extremes of the distribution. One primer pair for the locus wmc41 showed association with protein content. This was further confirmed through selective genotyping. The co-segregation data on the molecular marker (wmc41) and protein content on 100 RILs was analysed by means of a single-marker linear regression approach. Significant regression suggested linkage between wmc41 and a QTL (designated as QGpc.ccsu-2D.) for protein content. The results showed that this marker-linked QTL accounted for 18.73% of the variation for protein content between the parents. The marker has been located on chromosome arm 2DL using nulli-tetrasomic lines and two ditelocentric stocks for chromosome 2D. Received: 25 August 1998 / Accepted: 5 January 1999     

Comparison of the Drought Stress Responses of Tolerant and Sensitive Wheat Cultivars During Grain Filling: Changes in Flag Leaf Photosynthetic Activity,ABA Levels,and Grain Yield

Water status parameters, flag leaf photosynthetic activity, abscisic acid (ABA) levels, grain yield, and storage protein contents were investigated in two drought-tolerant (Triticum aestivum L. cv. MV Emese and cv. Plainsman V) and two drought-sensitive (cvs. GK élet and Cappelle Desprez) wheat genotypes subjected to soil water deficit during grain filling to characterize physiological traits related to yield. The leaf water potential decreased earlier and at a higher rate in the sensitive than in the tolerant cultivars. The net CO₂ assimilation rate (P _N) in flag leaves during water deficit did not display a strict correlation with the drought sensitivity of the genotypes. The photosynthetic activity terminated earliest in the tolerant cv. Emese, and the senescence of flag leaves lasted 7 days longer in the sensitive Cappelle Desprez. Soil drought did not induce characteristic differences between sensitive and tolerant cultivars in chlorophyll a fluorescence parameters of flag leaves during post-anthesis. Changes in the effective quantum yield of PSII (Φ_PSII) and the photochemical quenching (qP) depended on the genotypes and not on the sensitivity of cultivars. In contrast, the levels of ABA in the kernels displayed typical fluctuations in the tolerant and in the sensitive cultivars. Tolerant genotypes exhibited an early maximum in the grain ABA content during drought and the sensitive cultivars maintained high ABA levels in the later stages of grain filling. In contrast with other genotypes, the grain number per ear did not decrease in Plainsman and the gliadin/glutenin ratio was higher than in the control in Emese during drought stress. A possible causal relationship between high ABA levels in the kernels during late stages of grain filling and a decreased grain yield was found in the sensitive cultivars during drought stress.     

春小麦灌浆期籽粒沉淀值动态变化及氮磷肥与播期的影响

通过3个品质类型春小麦品种施肥和播期大田试验,建立了灌浆期籽粒沉淀值动态变化的曲线拟合方程,定量揭示籽粒沉淀值动态变化规律及氮磷肥与播期的影响效应.结果表明,自开花15 d始至成熟,籽粒沉淀值随时间变化呈先升高后降低的单峰曲线变化.在灌浆期籽粒沉淀值的动态变化过程中,不同基因型特点不同,且基因型间的关系也随之发生变化.各品种沉淀值积累速度的变化决定了成熟时高蛋白强筋品种沉淀值最高、高蛋白中筋品种次之、低蛋白弱筋品种最低.氮水平增加,高蛋白强筋和低蛋白弱筋品种沉淀值和曲线最高值降低,高蛋白中筋品种则明显升高;高蛋白强筋品种曲线最高值出现时间提前,而高蛋白中筋和低蛋白弱筋品种则推后.磷水平增加,高蛋白品种沉淀值和曲线最高值普遍提高,而低蛋白品种则降低;各基因型曲线最高值出现时间均推迟.氮磷（钾）素平衡配施是形成较高沉淀值的关键.在没有水分胁迫情况下,光温互作是影响籽粒沉淀值动态形成的首要条件,其次为降水;而≥10 ℃积温则为最敏感因子,即在较高光温条件互作前提下,增加灌浆期≥10 ℃积温则提高各基因型品种沉淀值.高蛋白比低蛋白品种更易受氮磷水平和气象条件影响.     

Leaf morphological plasticity and stomatal conductance in three Populus alba L. genotypes subjected to salt stress

The effect of salt stress on leaf morphology and functionality was studied in three Populus alba genotypes differing in tolerance to salinity: 6K3 (sensitive), 2AS11 (moderately tolerant), and 14P11 (tolerant). Plants were subjected to an intense and progressive salt stress from 50 to 250 mM NaCl by 50 mM steps at 10-day intervals. The micromorphological results highlighted phenotypic variation among the three genotypes already in control plants, with the genotype 14P11 having significantly smaller epidermal cells and higher stomatal density. Salt-treated plants modulated differently the expansion of stomata compared with epidermal cells. Regression analysis showed significant correlations between decrease of stomatal area and stomatal conductance (g_s) in genotypes 14P11 and 6K3. So, the common reduction of stomatal area could be an early mechanism to save water in this species. However, only genotype 14P11 showed further significant decrease of this trait under the highest salinity level, combined with a significant reduction in leaf length. In addition, this genotype showed the lowest leaf abscission rate at the end of salt stress period. The genotype 6K3 was severely affected by leaf necrosis and showed the highest leaf abscission rate in salt stress conditions. In the moderately tolerant genotype 2AS11, an intermediate plastic behaviour in both leaf morphology and physiology was observed during the experiment. The phenotypic variation among the three genotypes in terms of micromorphology and stomatal conductance is discussed in relation to plant functionality in salt stress conditions. Overall results suggest that leaf morphological habit contributes to salt tolerance in P. alba.     

Leaf Functional Traits and Stem Wood Characteristics Influencing Biomass Productivity of Mulberry (Morus spp. L) Genotypes Grown in Short-Rotation Coppice System

The present study was undertaken to obtain insights into the productivity determinant traits of mulberry (Morus spp. L.), a potential bioenergy tree crop. Our objectives were to identify leaf functional traits and stem wood characteristics that are correlated to biomass yield of mulberry. Based on the growth performance, six mulberry genotypes from different performance groups including high (Selection1 and Thaibeelad), average (Mysore Local) and poor (Triploid10, Jhoropakari and Selection1635) were selected for the study, along with a reference high-yielding genotype (Victory1). The study was conducted in Southern India for two consecutive years, covering two experimental seasons including exp season I (July 2009 to October 2009) and exp season II (July 2010 to October 2010). Mulberry trees were cultivated in a short-rotation coppice system under well-irrigated optimum farming conditions. Data were collected on biomass yield along with several leaf-level physiobiochemical characteristics and wood quality parameters. Significant genetic variation was recorded amongst the genotypes in most of the studied parameters. Fifteen out of a total of 22 traits, used in computing correlation coefficient matrix, were found to correlate with aboveground biomass yield. Light-saturated rate of photosynthesis, performance index, leaf nitrogen content, minimum leaf water potential and leaf-specific hydraulic conductance showed strong positive correlation with biomass productivity. Wood density, wood cross-sectional area and fibre cell density exhibited tight correlation with woody biomass yield. In conclusion, the identified 15 characteristics could be useful in the selection of suitable mulberry genotypes for higher biomass yield.     

The morpho-agronomic characterization study of Lens culinaris germplasm under salt marsh habitat in Swat,Pakistan

The present research study evaluate and identify the most suitable and high yielding genotypes of Lens culinaris for the salt marsh habitat of Swat in moist temperate sort of agro climatic environment of Pakistan. A total of fourteen genotypes were cultivated and analyzed through Randomized Complete Block Design (RCBD). These genotypes were AZRC-4, NL-2, NL4, NL-5, NL-6, NARC-11-1, NARC-11-2, NARC-11-3, NARC-11-4, 09503, 09505, 09506, P.Masoor-09 and Markaz-09. Different parameters i.e., germination rate, flowering, physiological maturity, plant height, biological grain yield, seed weight, pods formation and its height, pods per plants and protein content were focused specially throughout the study. Preliminary the Lentil genotypes have significant variability in all the major morpho-agronomic traits. The days to germination, 50% flowering and 100 seed weight ranged from 7 to 9, 110 to 116 days, and from 5.4 to 7.3 gm respectively. Biological yield and grain yield ranged from 5333 to 9777 kg ha⁻¹ and 1933 to 3655 kg ha⁻¹ respectively. Whereas, protein contents ranged from 23.21% to 28.45%. It was concluded that the genotype AZRC-4 is better varity in terms of grain yield plus in 100 seed weight and moreover, 09506 genotype was significant under salt marsh habitat in early maturing for the Swat Valley, Pakistan.     

Phylogenetic relationship of salt tolerance in early Green Revolution CIMMYT wheats

Twenty-five genotypes of early CIMMYT hexaploid wheat (Triticum aestivum L.) were screened for salt tolerance in a glasshouse experiment at 150 mol m⁻³ NaCl in sand culture. The genotypes Na(20)TPP, Penjamo 62, and Inia 66 exceeded all the lines in grain yield per plant under salt stress, whereas Nainari 60 and Norin 10 were the lowest of all genotypes. However, Jaral 66 and Yaqui 54 were the lowest of all the genotypes in all growth and yield attributes. Considerable variation in accumulation of Na⁺ and Cl⁻ in different plant parts of 25 genotypes of early CIMMYT wheat under salt stress was observed. The genotype Noreste 66 was the lowest in leaf Na⁺ and Cl⁻, and it had highest leaf K/Na ratio and K versus Na selectivity of all the genotypes, but in terms of growth and grain yield, it was moderately tolerant. The other genotype Norin 10 was the highest in leaf Na⁺ and Cl⁻ of all genotypes, but its leaf K/Na ratio and K versus Na selectivity were considerably low. However, in shoot biomass it was the highest and in grain yield the lowest of all genotypes. In view of phylogenetic lineage of the genotypes, most of the genotypes have evolved from Norin 10, so the trait of high uptake of Na⁺ and Cl⁻ in most genotypes may have been inherited from Norin 10. The ion exclusion trait in the moderately salt tolerant genotype Noreste 66 was possibly inherited from Yaqui 50 as it was the only among all putative parents which showed low uptake of toxic ions. Overall, owing to the complex nature of the salt tolerance trait being controlled by polygenes, it was not easy to draw relationships between degree of salt tolerance and pattern of uptake of toxic ions and maintenance of leaf K/Na ratios. However, from the phylogenetic lineage of the 25 genotypes it was possible to draw relationships between degree of salt tolerance and mechanism of ion uptake between parents and progeny.     

河南省花生地方资源蛋白质和脂肪含量分析及其育种利用策略

对233份河南省地方花生资源进行了蛋白质含量、含油量、油酸和亚油酸含量的全面测定,并与省外和国外资源的相关性状进行了比较分析。在河南地方品种资源中,蛋白质含量中等,平均含油量和油酸含量相对较高,但缺乏蛋白质含量超过30%或含油量超过56%、油酸含量超过70%的突出材料。河南省目前高油品种选育有明显进展,育成了一批高油花生品种,但育成品种蛋白质含量普遍偏低。提出了充分利用现有地方品种资源,积极采用远缘杂交、诱变、分子标记辅助选择技术及现代基因工程技术创制优良种质,选育优质专用品种的育种策略。     

不同生态环境与播种期下小麦籽粒品质变异规律的研究

选用 6个不同品质类型小麦品种在 4个生态点进行分期播种试验, 系统分析了不同生态环境下小麦籽粒产量与品质的变异特征及其与主要气候生态因子间的关系。结果表明 :生态点、品种以及地点×品种互作对籽粒产量、千粒重、蛋白质、湿面筋和淀粉含量、沉降值与降落值的影响均达到显著水平 ;不同播种期处理对产量与淀粉含量的影响达到极显著水平, 而播种期×品种互作对千粒重、降落值、淀粉含量及沉降值的效应达到显著水平 ;地点×播种期×品种互作仅对产量、湿面筋、淀粉含量与沉降值有显著的影响。在 4个不同生态点中, 南京点的籽粒蛋白质与湿面筋含量最低, 但淀粉含量最高 ;徐州点的产量和千粒重最大 ;泰安点的蛋白质含量与湿面筋含量最高, 沉降值最小 ;保定点的产量、千粒重最小, 但沉降值最大。不同播种期处理下, 适播与晚播的籽粒蛋白质含量、湿面筋含量、淀粉含量、沉降值与降落值都显著高于早播, 而早播期的产量和千粒重最大。各小麦品种在不同地点与播种期下产量与品质性状的变异中以降落值的变异系数为最大, 淀粉的变异为最小。开花至成熟期的日均温与淀粉含量呈线性负相关, 与产量、蛋白质和湿面筋含量及降落值呈二次曲线相关关系 ;日温差与产量和千粒重呈二次曲线相关关系, 籽粒蛋白质和湿面筋含量、沉降值及降落值则随昼温差的增加线性递增 ;开花至成熟期降雨量与产量、千粒重都呈现先升后降的二次曲线相关关系, 而与籽粒蛋白质含量和降落值呈现线性负相关关系 ;籽粒蛋白质和湿面筋含量与降落值随开花至成熟期的累计日照时数呈现线性正相关关系。     

Comparison of endogenous cytokinins, ABA and metabolites during female cone bud differentiation in low and high cone-producing genotypes of lodgepole pine

In lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), cone bud initiation within long-shoot buds varies according to genotype. We chose to study hormone profiles of two genotypes that differed significantly in cone yield. Phytohormone profiles were established by high performance liquid chromatography–electrospray ionization tandem mass spectrometry in multiple reaction monitoring mode with samples collected from genotypes 299 and 233, the typically high and low cone producers. Generally, concentrations of trans-zeatin-O-glucoside were higher in genotype 299, whereas dihydrozeatin concentrations were higher in genotype 233. Both isopentenyl adenine and isopentenyl adenosine were present at higher concentrations in genotype 233. The ratio of total quantifiable zeatin (Z)-type cytokinins to isopentenyl (iP)-type cytokinins was approximately threefold higher in genotype 299 during female cone bud differentiation. In genotype 299, ABA concentration was significantly lower than in genotype 233 on the first sampling date, while the phaseic acid concentration was lower consistently throughout the period investigated. Dihydrophaseic acid was present in low concentrations in most samples of genotype 233, but was not quantifiable in genotype 299. Our study reveals that long-shoot buds of the high cone-producing genotype had higher ratios of Z-type cytokinins to iP-type cytokinins than were found in the low cone-producing genotype. High cone-producing buds also contained less ABA, phaseic acid and dihydrophaseic acid during female cone bud differentiation.     

Genotypic difference of potato in carbon budgeting as a mechanism of phosphorus utilization efficiency

Observed genotypic difference in P utilization efficiency in soil grown potatoes led to the present study to investigate possible mechanisms of P utilization efficiency in potato genotypes grown in nutrient solution under three P regimes (low, medium and high). For all genotypes relative growth rate (RGR), leaf P content, net assimilation rate (NAR) and leaf area ratio (LAR) increased while P utilization efficiency and leaf starch content decreased at the two higher P regimes compared to the low P regime. The P-efficient genotypes CGN 17903 and CIP 384321.3 had higher RGR compared to the P-inefficient genotypes CGN 22367 and CGN 18233, which resulted from enhanced NAR rather than from LAR. Net photosynthetic rate was similar for all genotypes. However, for P-inefficient genotype CGN 22367, the lower NAR could be explained by increased leaf dark respiration. For P-inefficient genotype CGN 18233 we speculate that increased carbon cost of root respiration or exudation or both, caused low NAR, since leaf dark respiration of this genotype was similar to that of P-efficient genotypes.     

Specific Leaf Weight in Zones of Cell Division, Elongation and Maturation in Tall Fescue Leaf Blades

Patterns of change in specific leaf weight (SLW), water-solublecarbohydrate (WSC) content and leaf width were used to delineatethe region of secondary cell wall accumulation, and determinethe rate of increase in structural material along a developingleaf blade of tall fescue (Festuca arundinacea Schreb.). Structuralspecific leaf weight (SSLW) was determined by subtracting WSCmass from dry weight to emphasize structural material. Becausemeristematic activity, cell elongation, and cellular maturationare arranged successively in the grass leaf, these patternsrepresent a developmental sequence through which each segmentof the leaf blade passes. Patterns were generally similar fortwo genotypes, one selected for high (HYT) and the other forlow (LYT) yield per tiller, for a single genotype grown at 17or 25 C, and for two field-grown populations which differedin leaf area expansion rate (LAER). In all three studies, the elongation zone of the developingleaf had 31 to 39 per cent WSC on a dry weight basis. The LYTgenotype had a higher SLW at all stages of development whengrown at 17 than at 25 C, due to greater WSC accumulation.At 20 C, the HYT genotype had a higher SLW all along the elongatingleaf blade than the LYT genotype. This difference was due toa difference in SSLW, while WSC content was similar. The LERwas 64 per cent higher in the high population than the low,but elongation zones were similar in WSC. In all cases, SSLWwas high in the meristematic region, lowest near the distalend of the cell elongation zone, then increased linearly astissue matured. Rate of increase in SSLW was 8.5 and 5.2 g m^–2d^–1 for the HYT and LYT genotypes, respectively, and 7.6and 6.7 g m^–2 d^–1 for the high and low LAER populations,respectively. Festuca arundinacea Schreb., tall fescue, specific leaf weight, leaf width, water-soluble carbohydrates, leaf elongation rate     

人工高温下苋菜叶的抗热特征和光合性能

研究了连续6昼夜人工热胁迫(40℃/35℃)对苋菜(Amaranthus tricolor)两个栽培品种绿叶苋和花红苋叶片的组织结构、苋菜红素和热稳定蛋白含量及光合特性的影响。结果表明:6昼夜高温胁迫后,花红苋叶中苋菜红素大量积累,第6天时的含量是绿叶苋的1.81倍。苋菜红素在花红苋叶片下表皮、维管束细胞和上表皮中积累,但绿叶苋则不明显。花红苋栅栏组织结构正常,但绿叶苋出现部分断裂,叶绿体受损较为严重。花红苋叶片的叶绿素和类胡萝卜素含量降幅较绿叶苋低,热稳定蛋白含量轻微上升,其光补偿点和饱和光强比绿叶苋明显滞后。高温胁迫6 d后,绿叶苋的光合速率、胞间CO2浓度和气孔导度等光合参数均显著低于花红苋(P<0.01)。可见,高温下苋菜红素在组织或细胞中的积累与花红苋的耐热性密切相关,较好地维持了花红苋叶片相对稳定的光合性能。     

Interaction of NaCl and Cd stress on compartmentation pattern of cations,antioxidant enzymes and proteins in leaves of two wheat genotypes differing in salt tolerance

Physiological mechanisms of salinity–Cd interactions were investigated in inter- and intracellular leaf compartments of salt-tolerant wheat × Lophopyrum elongatum (Host) A. Löve (syn. Agropyron elongatum) amphiploid and its salt-sensitive wheat parent (Triticum aestivum L. cv Chinese Spring). In comparison with the intracellular fluid, only very low Na⁺ concentrations (up to about 4 mM) were found in the intercellular leaf compartment of wheat after a 75 mM supply of NaCl. NaCl salinity led to a higher Cd concentration in leaves of the salt-sensitive genotype. Cd in the intercellular leaf compartment was not detectable. Higher K⁺ concentrations in the intercellular leaf compartment of the salt-sensitive genotype suggest a higher plasma membrane permeability caused by NaCl + Cd stress. Ascorbate peroxidase (APX) activity was increased in leaves of the salt-sensitive genotype under the combined NaCl and Cd stress. The highest non-specific peroxidase activities were detected under the combined stresses. It is suggested that NaCl and Cd stress in combination enhance the production of oxygen radicals and H₂O₂, especially in leaves of the salt-sensitive genotype. As a consequence, disturbed membrane function may cause elevated Cd concentrations in the intracellular leaf compartment under salinity. Cd did not change protein concentration and pattern in leaves. The protein content in inter-and intracellular leaf compartments of both genotypes was increased under salinity. A different protein pattern was obtained in inter- and intracellular leaf compartments. Thus, several physiological interactions between NaCl stress and Cd were found in the two wheat genotypes.     

H-FABP基因多态性与江苏地方山羊品种IMF含量的关系

目的:探讨H -FABP基因多态性与江苏地方山羊品种肌内脂肪含量之间的相关性.方法:PCR - SSCP标记技术检测2个江苏地方山羊品种H -FABP基因部分外显子和内含子区域的多态性,利用最小二乘法分析其与IMF含量的关系.结果:在H - FABP基因第2外显子区域发现1个多态性位点,分别定义为GG和GC2种基因型.构建的固定效应模型显示,基因型GC的IMF含量含量高于基因型GG,在背最长肌和腿肌中GC基因型个体的IMF含量显著高于GG基因型(P＜0.05).结论:H-FABP基因第2外显子132 bp位点处GC基因型具有使IMF含量提高的遗传效应.     

土壤盐碱胁迫对春小麦K^＋、Na^＋选择性吸收的影响

通过对2种浓度土壤盐分胁迫下春小麦各品种不同时期各器官K^ 、Na^ 含量以及K^ /Na^ 的变化及其与抗盐性的关系研究,结果表明,随土壤盐浓度的升高,各品种的产量及各农艺性状值均有所下降,但不同品种的下降程度不同。随土壤盐浓度的升高,植株中K^ 、Na^ 含量均有所增加,但K^ 增加的幅度小于Na^ 的增加幅度,因而K^ /Na^ 呈明显下降趋势;在不同土壤盐分胁迫下,小麦品种K^ 、Na^ 随生育进程在体内各器官的分配发生动态变化,在分蘖期地上部K^ /Na^ ＞根部,孕穗期各器官K^ /Na^ 依次为：幼穗＞旗叶＞茎＞倒4叶,而灌浆期则依次为：籽粒＞旗叶＞茎＞倒4叶,说明生长旺盛的器官拒Na^ 能力强于其它器官;不同品种的K^ 、Na^ 含量及K^ /Na^ 不同,一般抗盐性强的品种在各时期均具有较高的K^ /Na^ ,反之则K^ /Na^ 较低;小麦的籽粒产量在一定范围内与其植株地上部各器官的K^ /Na^ 中一定的正相关,其中与分蘖期植株地上部的K^ /Na^ 及叶（K^ /Na^ ）／根（K^ /Na^ ）呈极显著正相关,而与此时期的SNa^ K^ 相关性最强,γ为－0．9670。因而,以分蘖期的K^ /Na^ 尤其是SNa^ K^ 作为小麦田间抗盐性的指标,具有一定的可靠性。     

Evaluation of physiological traits for improving drought tolerance in faba bean (<Emphasis Type="Italic">Vicia faba</Emphasis> L.)

Among grain legumes, faba bean is becoming increasingly popular in European agriculture due to recent economic and environmental interests. Faba bean can be a highly productive crop, but it is sensitive to drought stress and yields can vary considerably from season to season. Understanding the physiological basis of drought tolerance would indicate traits that can be used as indirect selection criteria for the development of cultivars adapted to drought conditions. To assess genotypic variation in physiological traits associated with drought tolerance in faba bean and to determine relationships among these attributes, two pot experiments were established in a growth chamber using genetic materials that had previously been screened for drought response in the field. Nine inbred lines of diverse genetic backgrounds were tested under adequate water supply and limited water conditions. The genotypes showed substantial variation in shoot dry matter, water use, stomatal conductance, leaf temperature, transpiration efficiency, carbon isotope discrimination (Δ¹³C), relative water content (RWC) and osmotic potential, determined at pre-flowering vegetative stage. Moisture deficits decreased water usage and consequently shoot dry matter production. RWC, osmotic potential, stomatal conductance and Δ¹³C were lower, whereas leaf temperature and transpiration efficiency were higher in stressed plants, probably due to restricted transpirational cooling induced by stomatal closure. Furthermore, differences in stomatal conductance, leaf temperature, Δ¹³C and transpiration efficiency characterized genotypes that were physiologically more adapted to water deficit conditions. Correlation analysis also showed relatively strong relationships among these variables under well watered conditions. The drought tolerant genotypes, ILB-938/2 and Melodie showed lower stomatal conductance associated with warmer leaves, whereas higher stomatal conductance and cooler leaves were observed in sensitive lines (332/2/91/015/1 and Aurora/1). The lower value of Δ¹³C coupled with higher transpiration efficiency in ILB-938/2, relative to sensitive lines (Aurora/1 and Condor/3), is indeed a desirable characteristic for water-limited environments. Finally, the results showed that stomatal conductance, leaf temperature and Δ¹³C are promising physiological indicators for drought tolerance in faba bean. These variables could be measured in pot-grown plants at adequate water supply and may serve as indirect selection criteria to pre-screen genotypes.     

Deployment of diversity for enhanced crop function

Mixtures of genotypes are the norm in natural and seminatural ecosystems and subsistence agriculture but have been replaced by pure genotypes in modern agriculture to maximise profitability in high-input systems. However, crop function with respect to the stability of yield and quality in particular tends to be lost in this process. Diversity can be reintroduced into cropping systems as a trait not only to confer stability but also to exploit synergies between component genotypes, compensating for potential performance losses against the best performing genotype in any given season or location. Quality need not be compromised, and research has demonstrated practical development and deployment approaches, which challenge the assumed benefits of current approaches to agronomy and achieve enhanced crop function.