Effect of Temperature Hardening on Growth, Carbohydrate and Protein Levels in Three Grain Crops

The effect of seedling pretreatment at different temperature levels and periods of exposure on growth, pigments, carbohydrates and proteins was studied in three grain crops; sorghum, wheat and barley at different stages of growth. Greater shoot-dry weights were obtained in sorghum with exposure for 15 hrs at 40 °C in the flowering, in wheat for 2 hrs at 10 and 40 °C in the fruiting and in barley for 15 hrs at 0 °C in the flowering stage. Increased root-dry weights were achieved by wheat with exposure for 4 and 15 hrs at all levels even at 0 °C in the flowering and for 15 hrs at 40 °C in the fruiting stage. Chl_a and Chl_b were more responsive in sorghum to higher temperature pretreatments than either wheat or barley. In sorghum the temperature extremes (0 and 50 °C) had resulted in a substantial reduction of Chl_a, and Chl_b in the fruiting stage. Lower and higher temperature-pretreatments had resulted in total available carbohydrate reduction in shoot and root of sorghum and wheat at the early stage, but the reverse was true later in flowering. In contrast, lower and higher temperature pretreatments had increased shoot-protein in sorghum and wheat in the vegetative and in sorghum in the flowering stage. Root-protein was more responsive to low temperature-pretreatments in sorghum and barley during the fruiting stage.     

Seed Composition, Seedling Emergence and Early Seedling Vigour of Red Kidney Bean Seed Produced at Elevated Temperature and Carbon Dioxide

Understanding the influence of growth temperature and carbon dioxide (CO₂) on seed quality in terms of seed composition, subsequent seedling emergence and early seedling vigour is important under present and future climates. The objective of this study was to determine the combined effects of elevated temperature and CO₂ during seed-filling of parent plants on seed composition, subsequent seedling emergence and seedling vigour of red kidney bean ( Phaseolus vulgaris ). Plants of cultivar 'Montcalm', were grown at daytime maximum/nighttime minimum sinusoidal temperature regimes of 28/18 and 34/24 °C at ambient CO₂ (350 μmol mol⁻¹) and at elevated CO₂ (700 μmol mol⁻¹) from emergence to maturity. Seed size and seed composition at maturity and subsequent per cent emergence, early seedling vigour (rate of development) and seedling dry matter production were measured. Elevated CO₂ did not influence seed composition, emergence, or seedling vigour of seeds produced either at 28/18 or 34/24 °C. Seed produced at 34/24 °C had smaller seed size, decreased glucose concentration, but significantly increased concentrations of sucrose and raffinose compared to 28/18 °C. Elevated growth temperatures during seed production decreased the subsequent per cent emergence and seedling vigour of the seeds and seedling dry matter production of seed produced either at ambient or elevated CO₂.     

Effects of Light, Different Growth Media, Temperature and Salt Concentrations on Germination of Cotton Seeds (Gossypium hirsutum L. cv. Nazilli 87)

Laboratory experiments were conducted to study the effects of light, different growth media, temperature, and salt concentrations on the germination ratio, mean germination period, and the beginning of germination of cotton seeds, Gossypium hirsutum L., cv. Nazilli 87. All factors considerably affected the germination rate of cotton seeds, ranging from 47% at darkness to 96% at 16 h of artificial light. The mean germination period varied from 5.6 days at 15°C and 1.3 days at 30°C under illumination and lasted longer at dark. The germination ratio was 94 % without additional salt and decreased from 63 % at salt concentration of 175 mM NaCl 1⁻¹ to only 8.7 % at 300 mM 1⁻¹. The mean germination period ranged from 5.28 days to 13.50 days at salt concentrations of 0–300 mM NaCl l⁻¹, respectively.     

人工老化处理对大麦种子萌发早期胚乳内源激素的影响

采用高温高湿人工老化处理的方法,研究老化对大麦种子萌发早期胚乳内源激素的影响。结果表明：人工老化处理使4个大麦种子胚乳中赤霉素（GA₃）、吲哚乙酸（IAA）、玉米素核苷（ZR）、脱落酸（ABA）、油菜素内酯（BR）和茉莉酸甲酯（MeJA）含量发生明显的变化。在种子吸水阶段,经老化处理的种子胚乳内GA₃、ZR和BR含量均低于未老化处理,而IAA和MeJA含量高于未老化处理;随着种子萌发,经老化处理的GA₃、ZR和BR含量逐渐高于未老化处理,而IAA和MeJA含量低于未老化处理;经老化处理的ABA含量在萌发过程中始终高于未老化处理。     

Interaction of Salinity and Temperature on the Germination of Sorghum

Laboratory studies were conducted to investigate the effect of salinity × temperature interactions on the germination of sorghum. Sorghum bicolor (L.) Moench. Sorghum seeds were sown in petri dishes with saline solutions of varying concentrations (electrical conductivities of 0.01, 6.4, 12.2, 17.4, 22.6, 27.2, 32.1, and 37.2 dSm^-1) prepared with NaCl. The germination responses of the seeds were determined over a wide range of temperatures (15, 20, 25, 30, 35 and 40 °C) for a period of 8 days. Salinity × temperature interactions were highly significant at each counting date. Although, increased salinity resulted in decreased germination percentages, the detrimental effect of salinity was generally less severe at higher temperatures. Germination rate index, computed from germination counts taken every 2 days, was influenced by salinity and temperature in a similar pattern as final germination. Seed germination was more tolerant to salinity at germination temperatures of 30–40 °C than at 15–25 °C.     

Osmotically Primed Seed and Seedling Reactions to Variations in Day/Night Temperature

The effects of alternating day/night temperatures, varying in maxima and minima but all averaging 30 °C, on germination and seedling characteristics of Sorghum bicolor L. (Moench) were investigated. Seeds of sorghum CSV 15 were soaked in 2, 4 or 6 g NaCl l⁻¹ solutions for 2 days at 25 °C, soaked in water for 1 day at 25 °C, or untreated. After treatment, drying and storage, seeds were germinated at 30/30 (day/night), 35/25, 40/20 or 41/19 °C temperature regimes under a polyethylene glycol-induced drought level of −3 bar. Results revealed no advancement of germination percentage but a partial increase in germination speed by osmotic seed treatments. All three osmotic treatments also reduced the plumule/radicle ratio owing to a speculated increase in root over shoot growth. Temperature regimes significantly influenced both germination and seedling characteristics with the optimum temperature appearing to be 35/25 °C. Increasing the temperature amplitude from 30/30 to 35/25 °C increased germination speed, which was reduced by incremental increases in temperature amplitude to 40/20 or 41/19 °C.     

A Rapid Method for Measuring Freezing Resistance in Crop Plants

The objective of this study was to develop a technique based on chlorophyll fluorescence to assess freezing injury and resistance of leaves. Optimization was done with faba bean leaves and applicability to other crops was examined at winter and spring with types of barley, oats, rape and faba beans. Selected leaves from young hardened beans were subjected to standardized freezing tests with different minimum temperatures ( T _min) and fluorescence was monitored. After a dark period basic fluorescence ( F _O was induced by 0.2 μmol m⁻² s⁻¹ pulsed red light and maximum fluorescence ( F _m) was assayed at different light intensities. 1500 μmol m⁻² s⁻¹ rendered to give the maximum possible output of Fm and best differentiation of differently damaged leaves by F _n= F _m - F _O. Leaf temperature during measurement and during a short storage (± 2 h) should be kept at about 0°C to avoid biases between differently damaged leaves. The measuring spot on the leaf must be standardized since fluorescence response differed at the tip and base of a leaflet, but not between the two leaflets of a faba bean leaf. The applicability of F _rr (ratio of F _r of stressed to unstressed leaves) as a measure of resistance was demonstrated by comparison of winter hardiness of cultivars with freezing resistance calculated from the relationship of F _vr and the T _min used in freezing tests.     

Carbon and Nitrogen Transport during Grain Filling in Rice Under High-temperature Conditions

Rice ( Oryza sativa cv. Koshihikari) seedlings were grown in a sandy dune soil in pots with a basal dressing of N (0.5 g N), P and K. Two N treatments were applied, a +N treatment in which a top dressing of ¹⁵N-labeled 0.5 g N was supplied on July 20 and a −N treatment in which no additional fertilizer was supplied. During the grain-filling stage from August 6 to 13, plants were subjected to one of three temperature treatments; controlled low temperature, LT (day/night 28/23 °C), controlled high temperature, HT (35/30 °C) and uncontrolled glasshouse temperature, UT (day/night averages, 38/26 °C). All plants were then exposed to ¹³CO₂ for 1 h on August 11 in a growth chamber at 25 °C. On August 13, all plants were harvested and the ¹³C and ¹⁵N abundances and starch and sugar concentrations in the ears, shoots and roots were determined. The ¹³C content of the ear was lower in UT than in LT irrespective of the +N or −N treatment. The translocation of ¹⁵N to the ears was also slightly depressed in UT compared with LT. Under high-temperature conditions (HT and UT), the starch content per plant was reduced for −N, but for +N, it was not significantly different among the temperature treatments. A high accumulation of sucrose was observed in all plant parts under UT conditions. It is suggested that extreme high day temperatures during the grain-filling period may reduce starch synthesis in the grains and, especially so under N-deficient conditions. High temperatures also induce an accumulation of sucrose and a decrease in carbon and nitrogen transport from the shoots to the ears via the phloem.     

Effect of Low Soil Temperature on Weight Increase, Gas Exchange and Distribution of 14C-Assimilates in Seedlings of a Maize Hybrid

Seedlings of a maize hybrid sensitive to chilling initially grew in the growth chamber of the phytotron at 20/ 17°C (day/night) and after the formation of the fourth leaf, the soil temperature was lowered to 5°C. Under such growth conditions the dynamics of dry weight change, gas exchange and the distribution of ¹⁴C-assimilates in seedlings were examined. The low soil temperature inhibited daily growth of dry weight of whole seedlings more than their photosynthesis. Simultaneously, it was also responsible for a greater increase in dissimilative losses.
During 37 hours (day-night-day), following exposure to ¹⁴CO₂, dissimilation in seedlings in cool soil (5°C) and in non-chilling conditions amounted to 35.1 % and 23.4 % of assimilated ¹⁴C (AC), respectively. At lower soil temperature relatively high dissimilative losses were observed on the first day after exposure (23.5 %), lower at night (9.9 %) and the lowest on the following day - merely 1.7 % AC. Higher losses of ¹⁴C under chilling conditions occurring on the first day were a result of limited photosynthetic refixation of ¹⁴CO₂ At night, however, they were associated with a prolonged period of intensive translocation of assimilates to the stem. It was assumed that an excessive accumulation of assimilates in leaf blades might be an additional factor responsible for increased dissimilative losses at low temperature during the first twenty-four hours. In the third period of measurements, as a result of a limited transport of ¹⁴C, dissimilative losses were lower than in previous ones and were not dependent upon soil temperature.     

Soil Temperature Simulation with Varying Residue Management

Maintaining crop residue on the soil surface is an important part of conservation tillage. Although broad effects of residues on soil temperature (T_s) are well documented, the methods to predict soil temperatures under various surface residues and tillage conditions are limited. Using the T_s at 0-, 0.05-, 0.10-, and 0.30-m depths, we developed a simplified model to predict T_s for a uniform soil from air temperature (T_a) data. Data were collected under various tillage and surface residue conditions after wheat ( Triticum aestivum L.) harvest. Residue management treatments were disk, sweep, and no-tillage (with standing or shredded residues). The model predicts maximum and minimum T_s at 0-, 0.05-, 0.10-, and 0.30-m depths using maximum and minimum T_s measured at 2-m above the soil surface, residue mass, apparent thermal diffusivity, and initial Ts profiles. Mean absolute deviation between simulated and measured maximum and minimum surface T_s were 0.53 and 0.44 °C or less, respectively. Root zone maximum and minimum T, were simulated within 0.14 to 0.91 and 0.27 to 0.95 °C, respectively, of the measured T_s. Greater precision of maximum and minimum soil temperature predictions with depth was obtained by using apparent thermal diffusivity calculated from initial T_s profiles. The proposed model can be useful in predicting T_s profiles required for crop growth modeling.     

A Quantitative Method to Assess Freezing Resistance in Faba Beans

In order to quantify freezing resistance (R₅₀) of winter faba beans from a limited number of plants, leaves were exposed to artificial freezing stresses with different test temperatures (TT_i). Injury (I_i) was assessed by rating (score: 0—8) and by conductivity measurements. The basic assumption that I_i depends almost linearly on TT_i over a sufficiently broad range with a constant ΔI/ΔTT could be verified and hence a formula is presented to compute freezing resistance R₅₀= (I_i—I₅₀) ×ΔTT/ΔI + TT_i with I₅₀ being a medium injury. This formula allows to quantify resistance by assessing I_i after freezing test(s) with definite TT_i. About 25 leaves are required. Rating appeared preferable to conductivity measurements because of easier and quicker performance and a slightly better discrimination between samples of different resistance. Based on a standardized freezing test, ΔI/ΔTT was determined. Application of the formula with ΔI/ΔTT = 2.5 units/°C for unhardened and hardened leaves, restrictions and experiences are discussed.     

NaCl、Na2SO4和Na2CO3对绿豆种子萌发的影响

为明确不同盐胁迫对绿豆种子萌发的影响,以晋绿9号为试验材料,分别测定不同浓度（0.5%、1.0%、1.5%、2.0%、2.5%）的NaCl、Na₂SO₄和Na₂CO₃胁迫下种子的相对发芽率、相对发芽势、平均发芽天数、相对发芽指数和相对盐害率。结果表明,3种盐胁迫均能抑制绿豆种子的萌发,种子萌发的相对发芽率、相对发芽势、相对发芽指数随盐浓度增加而降低,平均发芽天数和相对盐害率随盐浓度的升高而增加;不同盐分胁迫与绿豆种子发芽率之间的回归方程表明,3种盐胁迫对绿豆种子萌发的抑制作用表现为Na₂CO₃>NaCl>Na₂SO₄,晋绿9号的耐盐极限浓度分别为Na₂CO₃ 2.062%、NaCl 2.816%、Na₂SO₄ 7.684%。     

褪黑素对低温胁迫下棉花种子萌发特性的影响

低温胁迫严重影响棉花种子萌发,为明确褪黑素对低温胁迫下棉花种子萌发的调控作用,本研究以海岛棉品种‘新海41号’为试验材料,分析不同褪黑素浓度处理对低温胁迫(15℃)下棉花种子的萌发特性、抗氧化酶活性、丙二醛(MDA)和过氧化氢含量影响。结果表明,低温下棉花种子发芽率、发芽势和发芽指数较常温对照分别降低17.41%、13.52%和74.96%,胚根长度降低40.35%,SOD、POD、CAT活性略有增高,MDA和H₂O₂含量有所增加。低浓度的褪黑素（10 μmol/L和20 μmol/L）处理显著增加了低温胁迫下棉花种子发芽势、发芽率、发芽指数以及胚根长度,增强抗氧化酶的活性,减少MDA、H₂O₂的产生,其中20 μmol/L褪黑素处理后,与低温对照相比SOD、POD、CAT活性分别上升3.53%、29.47%、3.45%,MDA和H₂O₂含量分别减少13.93%和8.08%。适宜浓度的褪黑素处理能有效缓解低温胁迫对棉花种子萌发的损伤,增强种子耐低温性,其中20 μmol/L褪黑素处理效果最好。     

平铺白珠种子萌发特性研究

为提高平铺白珠的繁殖效率,以采集的平铺白珠‘极速贵族’种子为供试材料,测量种子形态、千粒重、吸水特性;并通过培养皿滤纸萌发法统计不同GA₃处理和温度处理下种子的发芽率;将无菌萌发所获幼苗与常规播种苗长势进行对比。结果表明,平铺白珠‘极速贵族’种子属小粒种子(千粒重(0.2995±0.0111) g),种子种皮薄且透水性良好。GA₃浸种时间、GA₃浸种浓度和温度三者间存在交互作用,其中GA₃浓度和温度是影响种子萌发的关键因子,浓度为1000 mg/L的GA₃溶液浸泡种子12～24 h,环境温度为白天25℃、夜晚15℃的条件有利于促进种子萌发,种子发芽率可达90%以上,显著高于对照(64.67%)。无菌苗长势要优于常规播种苗,无菌萌发1500 mg/L GA₃预处理种苗的平均株高(12.17 mm)和平均根长(18.15 mm)均高于常规播种苗的株高(9.65 mm)和根长(13.31 mm),培养基配方为WPM+2.0 mg/L 6-BA+0.1 mg/L ...     

High-temperature Effects on Germination and Viability of Weed Seeds in Soil

The control of weeds by solar heating of the soil using transparent polyethylene (PE) sheets was studied in the field during the summers of 1994 and 1995. The maximum soil temperature under plastic cover at 5 cm depth averaged 53°C. At 5 cm soil depth, solarization increased temperature by about 9°C. In the non-solarized soils, such high-temperature days were fewer. A temperature of 55°C at 5 cm soil depths was recorded both in irrigated and non-irrigated mulched soils. However, mulched soil recorded 70% of the treatment period compared with 43% in unirrigated and mulched soils. Lower depths of 10 and 15 cm did not attain a temperature 55°C or 60°C on any day during the experimental period.
Solarization treatment with PE sheets significantly increased NO⁻₃—N and NH⁺₄—N in comparison with non-solarized plots. While uncovered plots showed significant increase in available phosphorus and marginally increased in potassium and electrical conductivity. Organic carbon content and pH did not vary under different treatments.
PE mulching for 30 days significantly reduced the number of weed seeds, specifically Avena fatua L. and Phalaris minor Retz., while Trianthema monogyna Linn, and Asphodelus tenuifolius Cav. were not affected much in comparison with the former. Melilotus indica (L.) All, was not at all affected by the solarization treatment studied. The solarization reduction index (SRI) was calculated for each weed species studied and it was concluded that weeds having a low SRI can be controlled more effectively than weeds with high SRI values. The heating effect from solarization decreased significantly with soil depth. The 30 days' soil solarization treatment in moist soil was more effective than the 10 and 20 days' heating treatment in moist and dry soils for weed control.     

不同盐胁迫下罗布麻种子耐盐性的比较研究

罗布麻作为一种重要的耐盐性植物,在盐碱地土壤生态修复和植物引种改良等方面具有极高的应用潜力,本研究旨在对罗布麻种子萌发阶段的耐盐性进行比较,分析不同浓度盐胁迫下罗布麻种子萌发的差异。试验以罗布麻种子为材料,设置不同浓度梯度的NaCl、Na₂SO₄、NaHCO₃在种子萌发阶段进行盐胁迫。结果表明：随着盐分浓度的升高,罗布麻种子的发芽率、发芽势、发芽指数均有所下降,低浓度盐胁迫对罗布麻种子萌发的抑制相对不显著,但高浓度盐胁迫抑制效果显著。随着盐浓度的上升,起始萌发时间会出现滞后现象,且NaCl对罗布麻种子起始萌发时间的滞后最明显,NaHCO₃次之,Na₂SO₄相较最不明显。罗布麻种子萌发对NaCl较敏感,抑制作用最强。同时NaCl对种子的萌发延缓作用高于其他2种盐。耐盐性结果比较显示,3种盐的耐盐适宜浓度、耐盐半致死浓度、耐盐极限浓度为Na₂SO₄高于NaHCO₃和NaCl,罗布麻对Na₂SO₄的耐盐极限浓度可达7.81%。相较于Na⁺~Cl^-型盐碱土引种栽植,罗布麻更适宜Na⁺~SO₄^2-型盐碱土。     

Einfluß von Monoethanolamin auf den Ertrag von Kulturpflanzen

Effect of monoethanolamine on yield of crops
I. Studies on the effect of monoethanolamine on the grain yield and the nitrogen household in cereal plants (pot experiments)
The effect of monoethanolamine (EA, applied as foliar spray, 10 mg per pot) on grain yield and yield components was investigated in pot experiments with spring barley, winter wheat, and winter rye. Under conditions of a moderate drought stress the applied EA increased the grain yield of spring barley from 5 % to 7 % (significance only at α= 0.05). A stimulating effect of EA on the grain yield of winter wheat and winter rye was also obtained.
The positive influence of EA on the grain yield of spring barley was reproducible under the conditions of a limited water supply in small-scale plot experiments (increase of yield about 9 %).
In case of spring barley and winter rye the increase of the grain yield by EA, applied at growth stage 31 (= DC 31) was connected with a greater number of ear-bearing tillers. The increase of the winter wheat yield resulted from more grains per ear of the tillers.
The enhanced formation of tiller grain mass and total tiller biomass by EA was in correlation with a higher nitrogen import into tillers (r = 0.8⁺). Since an export of N from the main shoots into the tillers was not observed a higher N uptake (≥ 6 %) was calculated from N balances. After a fertilization with ¹⁵N-labelled fertilizers the additional ¹⁵N uptake was 13 % to 20 %.
Possible stress reducing activities caused by EA are discussed.     

Effect of Soil Temperature on the Carbohydrate Status in the Potato Plant (S. tuberosum L.)

Seed tubers of the variety Ostara were raised in growth chambers of 16°C air temperature continuously. The vessels were placed in a water bath of automatic temperature regulation so that soil temperatures of 16°C and 28°C could be maintained. Four weeks after emergence the plants were treated with ¹⁴CO₂ and 24 hours later the plants were harvested. Three more treatments and time harvests followed in two weeks intervals. C-14 activity was determined in soluble carbohydrates, in insoluble carbohydrates, and in non extractable residues respectively of the various plant parts in order to obtain information about the translocation of assimilates in the plant.
While the plants at 28°C soil temperature reduced the soluble sugar levels to 50% up to 70 days after emergence, the plants at 16° brought it down to 33% much faster. — The C-14 activity in insoluble carbohydrates amounted to only 50 % in the plants at 28°C while at 16°C it was more than 2/3 (Tables 1 and 2). — The C-14 activity in non extractable residues is much less at 28°C than at 16°C (Tables 3 and 4). — The starch weight reaches only 30% of the value obtained at lower temperature 70 days after emergence (Table 5). — At the higher temperature starch is also increasingly transferred to the tubers but to a much lesser extent and not from the stems and stolons (Table 6).
Possible causes, particularly the role of phytohormones, and consequences are discussed.     

On the Variability of Harvest Indices

The harvest index Z is defined, for example for cereals, as the ratio between grain yield X and biological yield Y: Z = X/Y. For many purposes the variance of Z is of major interest. In this paper several approximations for this variance are derived and their accuracy was investigated. These explicit formulae depend on some characteristics (means, variances or coefficients of variation, covariances or correlations) of the component variables grain yield X and biological yield Y. It is shown that for most practical applications the approximation v²z = v²x + v²y - 2rv_xv_y provides a sufficient accuracy for numerical calculations (v_x v_y and v_z are the coefficients of variation for grain yield X, biological yield Y and harvest index Z and r denotes the correlation coefficient between X and Y). Some conclusions on the relations between v_x, v_y and v_z are derived.
Finally, all the theoretical investigations and results are demonstrated and applied to a numerical example of winter-rapeseed data.     

山东省羊主要精饲料瘤胃降解率和小肠消化率的研究

为了研究山东省羊主要精饲料瘤胃降解率和小肠消化率,本试验采用瘤胃尼龙袋法和改进三步体外法对山东省羊主要精饲料瘤胃降解率和瘤胃非降解蛋白(RUP)小肠消化率进行了测定,并对RUP小肠消化率与饲料常规养分进行了相关与回归分析。结果表明：（1）所测饲料中干物质及粗蛋白的瘤胃降解率以小麦(82.47%、83.79%)最高,全棉籽(51.33%、54.12%)最低;RUP小肠消化率以玉米蛋白粉(98.95%)最高,麸皮(74.34%)最低。（2）瘤胃粗蛋白降解率(Y)和瘤胃干物质降解率(X)的线性回归方程为：Y=11.62＋0.88X(R₂=0.933,P＜0.05);RUP小肠消化率(Y)与粗蛋白含量(X₁)及中性洗涤纤维含量(X₂)的线性回归方程为：Y=85.57-0.28X₁+0.24X₂(R₂=0.873,P＜0.05)。由此可知,利用饲料常规养分含量预测RUP小肠消化率是可行的。