Impact of landscape features on spring phenological phases of maple and bird cherry in Estonia

We analysed the spatial distribution of the pollinationof maple (Acer platanoides L.) and bird cherry (Prunus padus L.) in Estonia on the basis of phenological data from the time series for 1948–1995, in 27 observation points, and from the special field observation programme 1996–1999, in 46 observation points. Phenological maps show that these springtime phenophases spread in the landscape at a rate of 3–6 days per 100 km, with different rates in early and late springs. The maple has a steeper gradient on northeastern islands and the bird cherry on the western islands; the values of standard deviation have a similar spatial pattern. The distribution of phenological phases in Estonia is influenced by differences between the temperature regimes of the Baltic Sea and inland areas, different climatic conditions in north-eastern Estonia, local altitude-impact of uplands with an absolute height of 150–300 m asl, and the effects of bigger lakes and wetland areas. On the basis of spring phenology, three seasonally different landscape types can be determined in Estonia: (1) Relatively continental South-East Estonian Plain and uplands – have the earliest spring with the smallest deviations and stable intervals between phases, (2) Central, western and northern Estonian plains – with temperate influence of the temperature regime of the Baltic Sea, and big variations from year to year. Large variability is caused by the presence and duration of ice cover on the sea in cold springs, and direct access by warm air masses in early springs. (3) North-east Estonia – has the most boreal climate with longer snow cover and very late spring, influenced by arctic air masses, local influence of the Baltic Sea, uplands, and large wetlands.     

The Mediterranean vegetation: what if the atmospheric CO2 increased?

The atmospheric CO₂ content is expected to continue to increase and probably induce warming at the global scale during the next century. The impact of such an increase will affect the composition and distribution of ecosystems on the same scale. To predict the integrated whole-ecosystem response to the CO₂ increase in the Mediterranean region we used a vegetation biogeochemical model. This model (BIOME3) integrates monthly temperature and precipitation, some soil characteristics, cloudiness and CO₂ concentration as inputs to simulate the vegetation in terms of biomes.First we demonstrate the ability of the model to simulate past vegetation when tested versus pollen data. Second we use the vegetation model for different climate scenarios and report results of future changes in the Mediterranean vegetation.These simulations indicate that an increase of the atmospheric CO₂ to 500 ppmv, jointly with an increase of about 2 °C of the mean annual temperature, as simulated by several atmospheric general circulation models, should be accompanied by a severe reduction (more than 30%) of the present annual precipitation to change significantly the present vegetation surrounding the Mediterranean. When precipitation is maintained at its present-day level, an evergreen forest spreads in the eastern Mediterranean and a conifer forest in Turkey. In NW Africa, a woody xerophytic vegetation occupies a more extensive territory than today and replaces part of the present steppe area.     

Simulated impact of sea level rise on phreatic level and vegetation of dune slacks in the Voorne dune area (The Netherlands)

Effects of sea level rise and different coastline management options on the phreatic level in a coastal dune area are calculated, using a scenario with 60 cm sea level rise in the course of the next century, resulting from global climatic changes. Changes in the phreatic level - both lowering and rising - are evaluated for their effects on the dune slack vegetation, using a newly developed interaction model hydrology-vegetation. Some indications of changes in nature conservation values are presented.     

Near-future sea level impacts on coastal dune landscapes

Very little attention has been paid to the impact of global warming, especially sea level rise, on coastal dunescapes, despite the fact that these provide natural protection along many of the world's shorelines. This paper reviews likely responses given the IPCC climate change predictions to 2030AD, which include sea level rise in the order of 0.09 to 0.29m. It is envisaged that coastal dunes will react in a variety of ways dependent both on regional and local factors. Rising water levels will increase susceptibility to erosion, but the fate of released sediment, particularly the onshore/offshore partitioning, must depend on morphodynamic antecedence, and the propensity for periodic domain shifts. The release of material at the shoreline may allow construction of coastal dunes, to the point of progradation in some zones. The response of dune vegetation to a warmer, wetter climate is uncertain. Most of the main temperate dune species are C3 plants which given favourable conditions would respond positively to CO₂ enhancement. However local factors may offset such potential gains.     

Adaptation of endemic mediterranean Sternbergia candida Mathew Et T. Baytop in the continental climate of central anatolia

Sternbergia candida is an important endemic bulbous plant with beautiful white flowers. It grows on the rock slopes of Baba mountains under Lebanon Cedars in the Mugla province of Turkey with Mediterranean climate. The plant is vulnerable and endangered due to illegal collection for local and foreign flower industry. Fast developing tourism industry and rapid urbanization has also shown negative implications on its population. The study reports three years successful adaptation results of S. candida in the continental climate of Ankara in the Central Anatolia. Four groups of bulbs based on diameter (>2.45, 2.15–2.44, 1.85–2.14 and <1.84 cm) were collected from its natural habitat during March, April and May 1998 and were evaluated for frequency (%) of emergence, mean number of leaves per plant, mean plant height, frequency (%) of flowering, frequency (%) of fruit setting. mean number of bulbs per plant, and mean diameter (cm) of regenerated bulbs. All categories of bulbs could be multiplied and adapted successfully with variable frequency of fruit setting. However, the highest fruit set was recorded from 2.15–2.44 cm April collected bulbs. This indicated that the bulb diameter and collection time had clear implications on multiplication, propagation and adaptation of the plant.     

Water relations and keeping-quality of cut Gerbera flowers. II. Water balance of ageing flowers

Time course of fresh weight (F.W.), water content as percentage of dry weight of petals (W.C.), maximal water content after saturation of petals (W.C._max), relative water content of petals (R.W.C.), absorption rate (abs.), transpiration rate, water potential of petals (ψ), stem flow resistance (R_stem) and flower developmental stage of cut Gerbera flowers in solutions with chemicals were determined. In a solution with silver nitrate, an increase of R_stem was evident after 4 days, resulting in a decrease of abs., F.W., W.C., R.W.C. and ψ. A constant pH of the vase water of 3.5 could prevent this increase in R_stem. The pH of the vase water was influenced by the flower itself.When the increase of R_stem was prevented, the absorption rate was higher than the transpiration rate during the first 5 days after cutting, which resulted in an increase of F.W., W.C. and R.W.C. After day 5, absorption was lower than transpiration, the F.W., W.C., W.C._max and R.W.C. decreased, while ψ remained steady. It is suggested that the water deficit-water potential relationships of the petals change with age, resulting in a lower water-holding capacity of the petals.     

Growth characters and chemical constituents of Dracocephalum moldavica L. plants in relation to compost fertilizer and planting distance

Two experiments were carried out during two successive seasons to investigate the response of Dracocephalum moldavica L. (dragonhead) to various plant densities and compost applications. Compost levels had a promoting influence on most of vegetative growth parameters and accelerated essential oil accumulation and chemical constituents including total carbohydrate and photosynthetic pigments content. Similarly, wider plant spacing showed the greatest effect on growth components and chemical constituents. Generally, the maximum rate of compost (39.6 t/ha) combined with wider distance between plants (40 cm) had a favorable effect on most of growth characters. The same treatment gave the highest mean value for essential oil yield during the first season while the same compost rate combined with the medium distance (30 cm) gave the highest value during the second season. The main constituent of the essential oil was linalool followed by geranial. On the other hand, compost levels combined with different distances had a pronounced effect on the various essential oil constituents. It can be decisived that there is no significant difference between wider distance (40 cm) and medium one (30 cm); so, it can be recommended to apply the maximum level of compost (39.6 t/ha) combined with medium distance.     

The role of calcium in regulating photosynthesis and related physiological indexes of cucumber seedlings under low light intensity and suboptimal temperature stress

The response of photosynthesis, antioxidant enzyme activity, and proline content to low light intensity and suboptimal temperature in Cucumis sativa L. seedlings pretreated with either distilled water, 10 mM CaCl₂, 1 mM LaCl₃, 3 mM ethyleneglycol-bis-(2-aminoethyl) tetraacetic acid (EGTA) or 0.05 mM chlorpromazine (CPZ) were investigated. The results showed that 10 mM CaCl₂ led to an increase in photosynthetic rate (Pn), carboxylation efficiency (CE), ribulose 1,5-biphosphate carboxylase (RuBPCase) activity, chlorophyll content, peroxidase (POD) and catalase (CAT) activity, and proline content of cucumber seedlings under low light intensity and suboptimal temperature, in comparison with the distilled water-pretreated seedlings. However, LaCl₃, EGTA and CPZ were in contrast to CaCl₂. These results suggest that CaCl₂ has beneficial effect on photosynthetic adaptation to low light and suboptimal temperature stress in cucumber seedlings. This might be related to the observed increase in RuBPCase activity, alleviation of lipid peroxidation and enhancement of osmoregulation, with these effects being inhibited by LaCl₃, EGTA and CPZ.     

Postharvest sprouting of onion bulbs grown in different temperature and C02 environments in the UK

Summary

The effects of different mean growing season temperatures and C0₂ concentrations during bulb production on postharvest bulb sprouting in a common storage environment at Reading, UK, was examined in two cultivars of the Rijnsburger type of onion (Allium cepa L.). Crops were grown in the field in temperature gradient tunnels maintained at either 374 or 532 ppm C0₂. At crop maturity, cohorts of bulbs were harvested, transferred to a constant temperature room (at an average of 11.6°C) and the subsequent duration to sprouting recorded. The duration to the onset of sprouting (expressed as days in storage until the first bulb sprouted) was not affected by cultivar, mean growing season temperature or CO₂ concentration, and was 165 d. The subsequent rate of sprouting (expressed as bulbs per day) was a positive linear function of mean growing season temperature, but no effects of CO₂ or cultivar were detected. Mean rate of sprouting increased from an average of 0.036 bulbs per day at 12.3°C to 0.093 bulbs per day at 18.6°C. Rapid sprouting in storage was associated with lower levels of total non-structural carbohydrate in the bulbs at the time of harvest. Thus, postharvest susceptibility of onion bulbs to sprouting in storage is expected to increase in warmer crop production temperatures.     

“半封闭温室小气候改变对番茄发育及果实产量和保健化合物含量的交互影响”论文评述

针对气候变暖导致温室冬夏两季极端温度多发，尤其是夏季平均温度过高和相对湿度降低的
问题，以及这种小气候变化如何影响温室番茄生长和品质的问题，德国科学家提出一种新的温室小气候调
控策略，并撰文报道了为期2 a 的研究结果，本文介绍和评述了该项研究。在较高环境温度和伴随的高平
均温度情况下，可应用高压雾系统结合CO₂ 施肥的方法降低温室内温度，提高相对湿度和CO₂ 浓度。与
常规气候条件下的番茄相比，新温室小气候调控策略能有效促进植株生长，增加叶片干物质质量，优化每
个花序的产量构成，使总产量提高20%，脐腐病发生程度减轻，在春季试验还能显著增大果实；新温室小
气候调控策略能显著促进次生代谢物的形成，番茄红素、β- 胡萝卜素、酚类化合物含量分别提高49%、
35% 和16%，非水溶性和水溶性组分抗氧化活性分别提高18.5% 和35.4%。因此，新温室小气候调控策
略可提高番茄总产量及品质，有利于保健化合物的形成。     

Thiazolidinedione improves Alzheimer-like changes in the hippocampus of type 2 diabetic rats by Wnt pathway

AIM: The abnormal level of insulin and glycemia in type 2 diabetes mellitus(T2DM) are important risk factors of Alzheimer's disease (AD). To explore the mechanism that thiazolidinedione (TZD) decreases the incidence of AD in T2DM, we use TZD on T2DM rats for an intervention and detect the change of Wnt pathway before and after the intervention.METHODS: To establish a T2DM model, the rats were fed with high glucose, high fat and high protein for 8 weeks, and then injected with STZ. TZD was administered intragastrically for 2 and 4 weeks and the rats were divided into TZD2W and TZD4W groups, respectively. Plasma insulin level was measured by RIA method, and the plasma glucose was detected by glucose-oxidase method. Total tau level, the phosphorylation level of tau at individual phosphorylation sites and the level of amyloid β precursor protein(APP), β-catenin, glycogen synthase kinase-3β (GSK-3β) and PPARγ in rat hippocampus were analyzed by Western blotting. The activity of GSK-3β in the hippocampus of rats was determined using γ- -ATP and the specific peptide substrate. The level of APP was also determined by immunochemistry. The insulin resistant (IR) degree was valued by HOMA-IR.RESULTS: Glycemia level in T2DM and TZD2W groups was obviously higher than that in control group. No significant difference of glycemia level between TZD4W and control group was observed. Plasma insulin levels in all groups were evidently higher than that in control group. The IR degree in T2DM and TZD2W groups increased significantly as compared to control group, but no obvious difference between TZD4W and control group was observed. The level of phosphorylated tau protein at site Ser199/202 and Ser422, and APP level in hippocampus of T2DM rats were found to be notably raised as compared to control group, but the level of phosphorylated tau protein at those sites and APP level were decreased gradually. No change of the PPARγ level was found in the hippocampus in T2DM and control group, but a notable increase was observed after TZD intervention. There was a decrease in β-catenin level in hippocampus of T2DM rats, which increased after TZD intervention for 2 and 4 weeks. There was a rise of GSK-3β activity in T2DM rats, which decreased after intervention.CONCLUSION: These findings suggest that TZD may improve the AD-like changes in the hippocampus of T2DM rats by up-regulation of Wnt pathway, which acts before the insulin signal transduction in the contribution of AD-like changes in T2DM rats.     

补灌水平对宁南山区露地青花菜产量、品质及耕层水分动态的影响

为探究宁夏南部山区自然降水条件下露地青花菜的最佳补灌灌溉方案,采用大田田间对比试验,设置5个补灌水平,在宁夏原州区冷凉蔬菜基地开展补灌水平对土壤水分分布、青花菜产量、品质、水分利用效率的试验研究.结果表明,青花菜全生育期自然降雨主要集中在7月份,且占全生育期降雨量的78.49％,此月份无需补灌即可满足生育后期对水分的需...     

Effect of temperature on photosynthesis of lettuce adapted to different light and temperature conditions

Gas exchange of lettuce plants, pre-grown in growth chambers at different irradiances (18, 37, 70 W m^?2) and temperatures (6, 14, 22°C) were measured in the range of 2–22°C. In weak light (18 W m^?2) there was no increase in CO₂ uptake above 2°C, and even in 70 W m^?2 the highest rates were obtained at about 10°C only. The response of net photosynthesis of lettuce to temperature is diminished as a result of morphological plant adaptations, i.e. specific leaf area or top-to-root weight ratio. The temperature optimum for dry-matter production is much higher than that for CO₂ uptake. Therefore, photosynthesis is an unsuitable criterion for temperature control in greenhouses.     

Growth responses of some greenhouse plants to environment. III. Design and function of a growth chamber prototype

Growth chambers for the study of effects of temperature, air humidity and CO₂-concentration on plant growth, with or without supplementary artificial light, are described. Each chamber has a volume of 1080 1. The mean airflow at plant level is 0.22 m s^?1. The temperature is controlled within ± 0.5°C in the range from 10°C lower to 20°C higher than the ambient temperature at low solar radiation. In direct sunshine, the temperature may rise 1°C at floor level and the gradient from the floor to the upper part of the chamber may be about 2°C.The relative humidity is generally controlled within ± 4%, in the range from 50 to 95%.The CO₂-concentration is controlled within ± 5% of the desired value. The number of air changes in the chambers may be controlled from 0 to 20 h^?1.Tests revealed no significant difference between the chambers with respect to fresh weight production of lettuce, rose or chrysanthemum. There was, however, a significant effect from the position within the chambers.     

Flowering and changes in respiration in Asiatic hybrid lilies as influenced by bulb vernalization

Asiatic hybrid lilies, Lilium × elegans Thunb., ‘Red Carpet’ and ‘Sunray’ were used to investigate the effect of bulb vernalization at 2.5 °C on plant growth, flowering, and CO₂ production (respiration), and to use the CO₂ production pattern to monitor the time of flower bud initiation and development. Lily shoot emergence and flowering were accelerated when bulbs received 2.5 °C bulb vernalization; however, flowering was delayed when bulbs were stored at 20 °C before treatment at 2.5 °C; this indicated that bulbs were de-vernalized. The maximum CO₂ level, and the minimum level, reached in 78 h in non-vernalized bulbs and in 110 h in 6 weeks of 2.5 °C (6 weeks/2.5 °C) treated bulbs, was increased as the 2.5 °C duration was increased; this indicated that CO₂ level can be an useful parameter to measure the cold stimulus (i) accumulated in bulbs following bulb vernalization. The respiration rate higher than the predicted values of the best-fit curves derived from the quadratic equations was designated as Blip A and this was correlated to the time of flower bud initiation and development. Shoot elongation may follow the rise in carbon dioxide levels after reaching the minimum level. It is proposed that increased carbon dioxide levels higher than the predicted levels (Blip A), was correlated to the time of flower bud initiation and development. Measurement of carbon dioxide production upon receipt of bulbs may be a useful technique to provide important information for optimum vernalization treatments for bulbs that have accumulated different levels of low temperature stimulus after bulb vernalization.     

Floral induction (FI) in longan (Dimocarpus longan, Lour.) trees. III: Effect of shading the trees on potassium chlorate induced FI and resulting hormonal changes in leaves and shoots

Previous experiments demonstrated that treatment of longan trees with potassium chlorate (KClO₃) induces “off season floral induction” (FI) even in the absence of the naturally required cool temperature [Manochai, P., Sruamsiri, P., Wiriya-alongkorn, W., Naphrom, D., Hegele, M., Bangerth, F., 2005. Year around off season flower induction in longan (Dimocarpus longan, Lour.) trees by KClO₃ applications: potentials and problems. Sci. Hortic. 104, 379–390]. Potassium chlorate, however, cannot replace the presence of functional mature leaves and sufficient light intensity. Here we examined in more detail the effect of shade (about 10% of natural sunlight) on KClO₃ affected hormone concentrations/transport of leaves and shoot apical buds (SAB) and their interactions with FI.     

黄金宝树幼龄木枝系构型特征及影响因素

为分析黄金宝树(Melaleuca bracteata)幼龄木不同生长高度的枝系构型特征及影响因素,通过统计分析不同高度阶段的枝系构型指标,并采用主成分分析法分析影响枝系构型的因素。结果表明:随着高度的增加,树高、地径、冠幅均值、树冠体积、逐步分枝率1,2与枝径均值对枝系构型的影响趋于上升;总体分枝率、逐步分枝率2,3、逐步分枝率3,4与枝条倾角均值对枝系构型的影响则增减不一。第1主成分的贡献率在23.61%~60.32%间,当高度小于60 cm时,树冠体积、枝径均值及冠幅均值是影响枝系构型的主要影响因素;高度在60~80 cm时,树冠体积和冠幅均值是主要影响因素;高度在80~100cm时,逐步分枝率1,2和总体分枝率是该阶段的主要影响因素;高度在100~120 cm时,逐步分枝率1,2、冠幅均值及枝径均值为主要影响因素。高度超过120 cm时,逐步分枝率1,2的绝对值最大,说明其为该阶段影响枝系构型的主要因素。     

Quantifying the nitrogen retention capacity of natural wetlands in the large-scale drainage basin of the Baltic Sea

We estimate the nitrogen retention capacity of natural wetlands in the 1.7 million km² Baltic Sea drainage basin, using a wetland GIS data base. There are approximately 138,000 km² of wetlands (bogs and fens) in the Baltic Sea drainage basin, corresponding to 8% of the area. The input of nitrogen to natural wetlands from atmospheric deposition was estimated to 55,000–161,000 ton y¹. A map of the deposition of both wet and dry nitrogen is presented. The input from the human population was estimated to 255,000 ton y¹ in terms of excretory release in processed sewage water. There may also be leakage from forests and agricultural land into the wetlands. Due to lack of data on hydrology and topography, such potential nitrogen sources are not accounted for here. The capacity of the wetlands to retain the atmospheric deposition of nitrogen was estimated to 34,000–99,000 ton y¹. The potential retention by wetlands was estimated to 57,000–145,000 ton y¹ when the nitrogen input from the human population was added. If drained wetlands were to be restored and their area added to the present wetland area, the nitrogen retention capacity was estimated to increase to 196,000–261,000 ton y¹. Our results indicate that existing natural wetlands in the Baltic Sea drainage basin annually can retain an amount of nitrogen which corresponds to about 5–13% of annual total (natural and anthropogenic) nitrogen emissions entering the Baltic Sea. The ecosystem retention service performed by wetlands accounts for a substantial nitrogen removal, thereby reducing the eutrophication of the Baltic Sea.     

Physical and cellular structure changes of Rastali banana (Musa AAB) during growth and development

A study on the physical and physiological characteristics of Rastali bananas (Musa AAB) was carried out throughout the 12 weeks after emergence of the first hand to determine the optimum growth stage of Rastali bananas. The fruit length and diameter followed a trend similar to that observed in fruit fresh weight throughout fruit development, and three physiological stages (S1–S3) of sigmoid growth were identified. The growth rate was slow during S1 (1st to 4th week), rapid during S2 (5th to 10th week) and remained constant during S3 (11th and 12th week). Peel cells underwent periclinal growth, which was accompanied by an increase in fruit peel and pulp thickness as the fruit developed. Moreover, the pulp colour became more vivid and yellow as the fruit developed. The peel moisture content decreased while pulp moisture content increased during fruit growth and development. The pulp firmness increased from the first until seventh week, and it decreased from the seventh week until twelfth week of the experiment. Carbon dioxide (CO₂) production was the highest at S1. However, CO₂ production declined until the 10th week and remained constant at a low level of 50 mL kg⁻¹ h⁻¹ during S3. Ethylene (C₂H₄) could not be detected throughout fruit growth and development. Thus, Rastali bananas showed physiological maturity at week 11 and week 12 after emergence of the first hand with constant fruit growth.