Nomogramm zur Keimung von Wintergerste (Hordeum vulgare L.) zwischen Teigreife und Ernte in Abhangigkeit von Temperatur und Niederschlag

Nomogram of germination of winter barley ( Hordeum vulgare L.) between dough stage and harvest, as influenced by temperature and rainfall
Winter barley, cv. Katja , was cultivated on loess soil near Göttingen in three seasons (1982–1984). After passing the dough stage, barley seeds were separated at regular intervals and incubated at 12 °C for germination.
For the germination (Y, in probits), the following regression equation was found: Y = 3.91 + 0.1186 X₁– 0.0267 x₂, where x₁= daily mean temperature (°C), and x₂= quantity of rainfall (mm) in the four days before the separation of the seeds.
The relationship among germination, temperature and rainfall was presented in the form of a nomogram which shows a convenient method to solve the regression equation graphically.     

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.     

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.     

Effects of Low Temperature Treatment at Seedling Stage on Soybean Growth, Development and Final Yield

The after effect of continuous and variable chilling temperatures acting periodically for 7 days at seedling stage (day/night: 2/2°C, 5/5°C, 15/2°C, 15/5°C, 15/15°C and control–22/18°C) on growth, development and final yield of soybean cultivar Polan and Progres were investigated. The temperature decrease lengthened the duration of the vegetation period before flowering for both cultivars, which allowed compensation for the reduced–as an effect of chilling–rate of daily increments in the leaf area and the dry weight of the above-ground parts of the plants. The most important symptom of chilling treatment was a considerable increase in the number of axillary branches after flowering, which caused an increase in the dry weight of plants. The subsequent reaction of the growth of leaves to chilling at seedling stage was, after flowering, variety dependent. The area of leaves bigger at Polan or similar to control at Progres ensured good seed filling in an increased number of pods developed on axillary branches. Chill-induced delay in plants development allowed the avoidance of low temperature occurring during flowering in this experiment. This chilling during flowering was one of the reasons of worse-pod setting and reduction of seeds per pod number at control plants.     

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.     

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.     

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.     

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.     

Variability and Correlations in Grain Sorghum Genotypes (Sorghum bicolor [L.] Moench) Under Drought Conditions at Different Stages of Growth

Twenty-two genotypes of grain sorghum were grown under drought conditions by omitting one irrigation during stages of before flowering period, kernel filling period, and physiological maturity period at Assiut Univ. Farm in 1987 and 1988 seasons. The results obtained revealed that considerable variation existed among genotypes for all the studied traits. The most effective moisture stress treatment in reducing grain yield, panicle weight and plant height was during flowering stage. While 1000-kernel weight was much affected by moisture stress during grain filling period. The genotype x year interaction (σ²_gy) was large compared to genotype x irrigation treatment (σ²_gl) indicated that genotypes responded differently when they were grown from year to year. The genotypic variance (σ²_g) for all traits were large reflecting the importance of genetic variability. Both phenotypic and genotypic correlations among traits showed that plant height and 1000-kernel weight were highly correlated with grain yield, while leaf area index was low associated with plant height.     

Effects during Period of Siliqua Developing of KH2PO4 and MgSO4 Application on Nitrogen Transportation in Pods of Oilseed Rape(Brassica napus L.)

An experiment was conducted in field experiment plot to investigate nitrogen transportation from hulls of pods in different periods at early stage of siliqua developing and effect of KH₂PO₄ and MgSO₄ application on it using ¹⁵N-urea.
More than 80 % of ¹⁵N applied on the surface of pods at lower terminal during flowering was recovered from all pods one month after flowering, most of them were still in the hulls of labelled pods, 17-27 % of ^l5N applied was transported into seeds, a small amount was transported to pods at upper terminal, a little amount was found in pods at branch. More ^l5N applied in middle period of flowering was transported to pods at upper terminal and branch than those applied in early period of flowering. It should be further investigated to conclude how will be going on transportation of nitrogen from hulls as preceding of siliqua developing towards maturity of seeds and its difference between ¹⁵N applied in more different periods.
Application of KH₂PO₄ and MgSO₄ with ¹⁵N-urea of surface of pods promoted transportation of ¹⁵N into seeds from hulls, effect of MgSO₄ was more notable.     

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.     

Electrolyte Leakage, ATP Content in Leaves and Intensity of Net Photosynthesis in Maize Seedlings at Permanent or Different Daily Exposure to Low Temperatures

Changes were determined in electrolyte leakage (EL), ATP content in leaves and intensity of net photosynthesis (FJ in maize seedlings as a result of continued exposure to low temperatures for several days or, after a cold night (5 °C, 9 h), alternating application of 5 °C and 20 °C temperatures during the lit phase of the day (h of chilling during day/night: 0/9, 5/9, 10/9, 15/9).
At continuous exposure to low temperatures, permanent reduction of ATP content occurred between days 7 and 10, while EL increased significantly between days 4 to 7 (depending on experimental conditions). Of three leaves differing in age, most injuries were found in the oldest leaf. An increased intensity of irradiation from 150 to 500 μE. m⁻².s⁻¹ caused an earlier decrease in the ATP content and a further increase in electrolyte leakage. ATP content showed a 24 h rhythm, it increased at the end of the night and decreased at the end of the day. The rhythm was particularly noticeable in the control plants (20 °C), as well as, however to a lesser extent, in plants exposed to daily fluctuating chilling temperatures. It has also been observed that higher temperatures occurring in day time may diminish electrolyte leakage induced by previous low temperatures
The intensity of F_n determined at 20 °C, 4 h after withdrawal of chilling, decreased with the prolongation of the chilling period during the day.
Thus, it may be assumed that the EL and F_n values as indicators of the plants' sensitivity are in better agreement with the induced chill doses than the ATP content in leaves, which to a greater extent depends on the interaction between chilling and other experimental factors, such as irradiation intensity or the sequence of light and darkness.     

Effect of Storage Conditions on Germination in Wheat

The percentage germination was determined for storage of wheat at four grain moisture contents (15, 18, 21 and 24 %), four temperature levels (4, 15, 25 and 40°C) and three levels of mechanical damage (0, 15 and 30 %). The effect of each level of moisture was investigated using three replicates for each temperature and each level of mechanical damage. During storage, at 0.25, 0.5 and 1 % dry matter loss (DML), germination tests were carried out on samples taken from each of the above treatments. The percentage germination was compared statistically amongst treatments. The analysis showed significant differences among most of the treatments. The percentage germination decreased very slowly at a low moisture level (15 %), low temperature (4°C) and low level of damage (0 %), while it decreased rapidly at a high moisture level (24 %), high temperature (40°C) and high level of damage (30 %). For example, the percentage germination was 41 % when the wheat was stored at 4°C, 15 % mechanical damage and 24 % moisture content after a storage time of 36.5 days, while the percentage germination was 88.3 % when the wheat was stored at 4°C, 15 % mechanical damage and 15 % moisture content after a storage time of 104 days.     

Photosynthetic Activity and Soluble Carbohydrate Content Induced by the Cold Acclimation Affect Frost Tolerance and Resistance to Microdochium nivale of Androgenic Festulolium Genotypes

The aim of the experiment was to verify whether changes in photosynthetic activity measured by means of chlorophyll fluorescence techniques and soluble carbohydrate level induced during pre-hardening and cold acclimation in androgenic forms of Festulolium are related to their winter hardiness and pathogen resistance. The study was performed on six androgenic genotypes of Festulolium, which differ in their degrees of winter hardiness. The chlorophyll fluorescence parameters and sugar content were measured in the control plants, pre-hardened at 12 °C and cold-acclimated at 2 °C. Cold acclimation at 2 °C, preceded by pre-hardening at 12 °C, induced a decline in maximum PSII quantum efficiency ( F _v/ F _m) and in non-photochemical quenching (NPQ). Exposure to 2 °C also resulted in reduced efficiency of energy conversion in photochemical processes ( q _p). The soluble carbohydrate amount increased in the susceptible genotypes and was associated with a decline in NPQ and current quantum yield of PSII (φ_PSII). In resistant plants, a decrease in the sugar content was observed, which could be explained by their consumption in metabolic processes initiated during cold acclimation. The changes in sugar content were associated with a decline in NPQ and q _p.     

Waterlogging Affects Leaf and Tillering Dynamics in Wheat and Barley

The aim of this study was to analyse (i) the crop attributes that determine flowering time (i.e. final leaf number, FLN; and phyllochron, Phy), (ii) the dynamics of tiller appearance and (iii) the synchrony between leaf and tiller appearance in wheat and barley plants exposed to waterlogging. Two experiments were carried out in pots, in which wheat and barley cultivars were exposed to five waterlogging treatments, during different periods throughout the crop cycle, from emergence to maturity. The appearance of leaves and tillers on the main stem was measured twice a week in labelled plants. Waterlogging from emergence to flag leaf appearance significantly delayed time to flowering. The delay was greater when waterlogging occurred at the beginning of tillering, lengthening the period from emergence to flowering 24 % (13–15 days) in barley and 10–15 % (6–10 days) in wheat, as compared to control. Phy was the main attribute explaining the delay in flowering, as FLN was not altered. Waterlogging during the early stages of development reduced tiller appearance rate (TAR) in both species, but this effect was partially counterbalanced by a lengthening of the tillering phase, so the effect on final tiller number at maturity was limited. In conclusion, the exposure of wheat and barley to waterlogging during early stages of development delayed time to flowering and reduce TAR in both species. Waterlogging during more advanced crop stages produced slight effects on tillering dynamics, which would indicate that waterlogging affected structure generation more than mortality.     

Einfluß der N-Düngung auf Ertragsentwicklung landwirtschaftlicher Kulturen und Veränderung des mineralischen N-Gehaltes im Boden bei achtjährigen Dauerversuchen

Influence of long-time Nitrogen-fertilizing on yield response of agricultural crops and mineralized Nitrogen in soil
In the years 1979–1986 a fertilizer trial with increasing Nitrogen amount was performed in order to prove the N_min-method according to S charpf and W ehrmann . The N_min-method regards the mineralized N in soil (N_min) for optimizing the N-fertilizer amount at the begin of vegetation, could be confirmed. The optimal N-rate (including N_min) was for winter wheat and winter barley 120 kg/ha, winter rye 100 kg/ha and sugar beet 200 kg/ha. For cereals additional N-rates were given at the end of tillering 20 kg/ha N and at ear emergency 60 kg/ha N. For the optimal N-fertilizing system we found a positive N-balance (input-output) in a range of 10–25 kg/ha. The influence of N-fertilizing on the mineralized N-amount in soil was very small comparing to influence of weather, soil type or crops. Only at one location a little increase of N_min (10–15 kg/ha) could be observed after a positive N-balance (50 kg/ha).     

Nachweis des Strohabbaues über die Stickstoffreisetzung aus 15N-markiertem Stroh

Ten charges of ¹⁵N-labelled straw with different C/N ratios were incubated with lightly loamed sand at 25 °C and 50 % of the maximum water capacity. At the start of the 18-week incubation, mineral nitrogen was added and the ¹⁵N_min (NH₄ and NO₃-N) content was determined six times during the course of the experiment. A slow release of ¹⁵N was observed. After 111 days, between 2.5 and 13.0% of the total applied ¹⁵N was mineralized. The addition of ammonium sulphate caused an increasing degradation of organic N compounds of the straw material even during the first weeks. Finally, between 6.4 and 33.3 %¹⁵N was released. The ¹⁵N release only partially shows the straw degradation.     

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.     

The effect of temperature on seed set and embryo development in reciprocal crosses of wheat and barley

Summary The effect of temperature on seed set and embryo development in reciprocal crosses of barley and wheat was assessed in crosses involving two spring barley varieties (Betzes, Martonvásári 50) and one wheat variety (Chinese Spring). Detached tillers placed in nutrient solution were pollinated in controlled environments at constant day-night temperature regimes (12, 15, 18 and 21° C) with a light intensity of 30,000 lux and a relative humidity of 80%. When barley was used as the female, lower temperatures (12 and 15° C) produced the maximum seed set, whereas for the reciprocal cross, the highest temperature (21° C) produced the best seed set in the Chinese Spring × Betzes combination.Low temperature retarded the embryo development. The highest numbers of hybrid plants were produced at 18° C and 21° C in the barley × wheat cross and in the wheat × barley cross, respectively. Embryos of about 1.5 mm length in the barley × wheat cross, and of about 1.0 mm length in the wheat × barley cross germinated successfully. The smallest embryo giving rise to hybrid plants was 0.57 mm in the barley × wheat cross and 0.51 mm in the wheat × barley cross.     

2001—2020年藏东南苹果物候期变化特征分析

开展气候变化对苹果物候期的影响研究,可为应对气候变化和指导当地苹果生产提供科学依据。利用2001—2020年林芝苹果物候期和逐日平均气温(T_m)、最高气温(T_max)、最低气温(T_min)、相对湿度(RH)、降水量(Pr)和日照时数(S)等资料,采用线性倾向估计法、Pearson相关系数和优势分析方法等,分析了苹果物候期及生长期长度的变化趋势,以及影响的主导气候因子。结果表明：2001—2020年藏东南苹果各物候期均呈推迟趋势,为2.11~10.20 d/10 a,以开花始期推迟的最多;春季物候期较秋季物候期推迟的明显。果实生长发育期和果树生长季分别以8.10、1.59 d/10 a的速率缩短,这与中国苹果主产地延长趋势不同。果树生长季内,只有Pr、RH、S呈下降趋势,其他气候要素趋于上升。其中,可采成熟期之前T_m、T_max、T_min、Pr趋于增加,之后呈下降趋势。影响物候期长度的主导气候因子,除叶变色末期—落叶末期是S外,其他物候期为∑T₀。研究区3月上旬T_max每升高1℃,开花始期提前3.29天;8月下旬T_m平均升高1℃,可采成熟期推迟3.15天。