Early Vegetative Period Research Articles

Waterlogging Response of Lentil Cultivars Grown in Greenhouse Throughout The Early Vegetative and Recovery Period

Under conditions of global climate change, the frequency of climate anomalies is predicted to increase. One of these issues is the problem of waterlogging in agricultural areas as a direct result of the unexpected and severe rainfall that has occurred over the last decades. In this study, the morphological responses to waterlogging stress and the recovery capacity of the lentil cultivars were investigated. A waterlogging stress study was conducted in small water pools with four different lentil varieties (Çağıl, Fırat 87, Kafkas and Kayı). Lentil cultivars were exposed to waterlogging stress for 7 and 14 days in the same greenhouse conditions. Measurements were taken at the end of 7 and 14 days of waterlogging (W-7 and W-14) and during the recovery period after flowering (R-7 and R-14). Lentil cultivars and plant traits were negatively affected by waterlogging stress applications (W-7 and W-14). According to the study, 14-day waterlogging had a greater impact on lentil cultivars than 7-day waterlogging. Total biomass measured after flowering at R-7 and R-14 waterlogging decreased by about 31.5% and 49.3%, respectively. Çağıl cultivar had a tolerance to waterlogging stress, but Kafkas cultivar was sensitive to waterlogging stress.

Effects of Seed Priming and Foliar Treatment with Ascorbate, Cysteine, and Triacontanol on Canola (Brassica napus L.) under Field Conditions

Studies conducted in controlled environments showed that seed priming and foliar treatments with various bioactive substances can stimulate germination, uniform seedling emergence, photosynthesis, and nutrient uptake efficiency and can lead to increased productivity, crop stand, and quality. Only a few studies provide a comparative experimental outlook about the use of the bioactive substances in open-field cultivated canola. The aim of this study was to investigate the effects of seed priming and foliar treatment with ascorbate (AsA), cysteine (Cys), and triacontanol (Tria) on the growth and yield parameters of two canola cultivars rapeseed cultivars (“Factor” and “Hybrirock”) under open-field conditions for three growing seasons under temperate conditions from Central Transylvania. Plant growth and yield parameters were recorded at different plant development stages: in autumn (early vegetative period), in spring, and at harvest. Not all substances that have undergone laboratory testing were successful in the field. Seed priming with 10 ppm Cys and AsA had beneficial effects on the development of seedlings, whereas their foliar application enhanced the number of silique, seed yield, and the oil content of the studied canola cultivars. The effects of Tria were visible on the biometrics parameters only in autumn and spring, and also on the root parameters, but in some cases, 10 ppm Tria had no effect on plants, or even a negative effect could be observed on important parameters for agriculture such as estimated seed yield, seed yield/plant, and oil content. Optimizing treatment and application by determination of the lowest effective concentration, together with the frequency of treatments and persistence effects are crucial for cost-effectiveness.

Attraction of the Biocontrol Agent, Galerucella placida Towards Volatile Blends of Two Polygonaceae Weeds, Rumex dentatusand Polygonum glabrum.

The Polygonaceae weed, Rumex dentatusL. grows in association with wheat, mustard and potato, while Polygonum glabrum Willd. grows in association with rice in India. Both larvae and adults of Galerucella placida Baly (Coleoptera: Chrysomelidae) voraciously consume these weeds. Applications of synthetic herbicides to control weeds are harmful to the environment including beneficial organisms. We propose to find volatile organic compounds (VOCs) from both weeds causing attraction of the biocontrol agent, G. placida, in order to attempt to use the insect as a biological weed control. Behavioral responses of G. placida towards volatile blends characteristic of undamaged (UD), insect-damaged (ID), jasmonic acid-treated (JA) or mechanically-damaged (MD) plants were conducted by Y-tube olfactometer bioassays. Cuminaldehyde was predominant in VOCs of UD R. dentatus, ID P. glabrum, and both JA and MD R. dentatus and P. glabrum. Geraniol was predominant in VOCs of UD P. glabrum, while 1,3-diethylbenzene predominated in VOCs of ID R. dentatus. Females were more attracted towards volatile blends of ID plants compared to UD or JA plants. Females did not show attraction towards volatile blends of JA plants. We identified two bioactive synthetics blends, one comprised of seven compounds - 16.65µg 1,3-diethylbenzene, 10.72µg acetophenone, 6.52µg 2,6-(E,Z)-nonadienal, 2.46µg 1-nonanol, 4.19µg decanal, 9.86µg 4-ethylacetophenone and 3.34µg 1-hexadecene dissolved in 25µl CH2Cl2 and the other containing five compounds - 2.50µg 2-octanol, 6.84µg limonene, 0.64µg dodecane, 6.63µg 4-ethylacetophenone and 0.24µg geranyl acetone dissolved in 25µl CH2Cl2. These two blends of volatile compounds could be used to attract the biocontrol agent during early vegetative period of these two weeds, which could lead to eradication of weeds from crop fields.

Do corm seeding rate and planting depth influence growth indicators of saffron (Crocus sativus L.)?

Saffron, the primary in the market now, is a food spice by far the world’s most expensive. In order to study the effects of different corm seeding rates and sowing depth on physiological indices of saffron, an experiment was conducted as a factorial layout based on randomized complete block design with three replications at the research farm of the Ferdowsi University of Mashhad during 2015–2017 years. The experimental treatments were all combinations of different corms seeding rates in four levels (7, 8, 9, and 10 Mg ha−1) and sowing depth in three levels (10, 15, and 20 cm). The studied traits were the dry weight of mother and daughter corms, cumulative dry matter, and some growth indices such as leaf area index (LAI), crop growth rates (CGR), relative growth rate (RGR), and Leaf Area Ratio (LAR). The results showed 8 Mg ha−1 corm seeding rate and 10 cm sowing depth increased total crop dry weight, CGR, and RGR in saffron. Based on obtained results at the beginning of the vegetative growth period, CGR declined for a short time. So that by continuing the vegetative growth, the plant reached on growth compensation point, and then CGR increased. From 180 days after the sowing date and in the late stages of vegetative growth, the growth rates trend decreased again. The results also showed that the LAR trend decreased from the early vegetative growth period, which can be explained by the faster growth of the daughter corms and other underground parts of the plant than the leaves during the early vegetative growth period. According to the results and the natural trend of mother corm breakup during the growing season, increasing density due to increasing competition between mother corms caused intensification in a weight reduction of mother corms in the late stages of the growing season. Also, in the first three months after sowing, daughter corms did not grow anymore, and the beginning of their growth coincided with the end of the saffron flowering period.

Prediction of grain protein content and gluten quality of bread wheat in the early vegetation period by optical sensors

Estimation of the end-use quality characteristics of bread wheat in the early phenological period and before harvest is critically important for the flour industry. This study investigated the usability of the Normalized Difference Vegetation Index (NDVI) and Chlorophyll Meter (CM) values obtained by GreenSeeker and Chlorophyll Meter for prediction of protein content and gluten quality in the early growth stage of bread wheat. The results demonstrated that protein content was positively correlated with NDVI and CM values of the optical sensors, which can be predicted by using the equation developed with NDVI Zadoks (ZD)3.1 period values (R2 = 0.92, p <0.01). Compared to the NDVI values, higher correlated equations were obtained with the CM for the sedimentation volumes. Both sensor readings showed strong correlation with the GlutoPeak GSI (Gluten Strength Index) and GRI (Gluten Rheological Index) values in the ZD3.1 period. Also, while Cu, Fe and Mn contents of the grain tended to increase with increasing nitrogen doses according to both optical sensor readings, Zn content was inversely proportional to the NDVI and CM readings. The results of this study reveal that the grain protein content and gluten quality of bread wheat can be estimated successfully in the ZD3.1 period.

Attraction of the biocontrol agent, Lema praeusta, towards two Commelinaceae weed volatiles

AbstractTwo Commelinaceae weeds, Commelina benghalensis L. and Murdannia nudiflora (L.) Brenan, are abundant in rice fields of India. Larvae and adults of Lema praeusta (Fab.) (Coleoptera: Chrysomelidae) voraciously consume these two weeds. Synthetic herbicides are applied to control both weeds, but applications of these substances have harmful effects in environment and beneficial organisms. So, it is necessary to use native biocontrol agent to control these weeds. Hence, an attempt has been made to find volatile organic compounds (VOCs) from both weeds causing attraction of L. praeusta. Behavioural responses of L. praeusta towards volatile blends from undamaged (UD), insect‐damaged (ID: plants after 6 or 48 hr of continuous insect feeding) and mechanically damaged (MD) plants were conducted by Y‐tube olfactometer bioassays. Benzyl alcohol was predominant in VOCs of UD plants and M. nudiflora after 48 hr of insect feeding. Benzyl alcohol and cuminaldehyde were both predominant in VOCs of C. benghalensis after 48 hr of insect feeding. Females were more attracted towards volatile blends from plants after 48 hr of insect feeding compared to undamaged plants. Females showed attraction towards a synthetic blend of seven compounds—7.28 µg (Z)‐3‐hexen‐1‐ol, 0.93 µg trans‐isolimonene, 19.18 µg benzyl alcohol, 0.16 µg undecane, 1.07 µg 1‐nonanol, 1.23 µg 1‐undecanol and 0.47 µg 1‐eicosene resembling the amounts released by C. benghalensis after 48 hr of insect feeding during 1 hr or a synthetic blend of six compounds—18.10 µg benzyl alcohol, 0.25 µg undecane, 0.56 µg 1‐nonanol, 1.37 µg 1‐undecanol, 0.35 µg 1‐eicosene and 2.19 µg phytol resembling the amounts released by M. nudiflora after 48 hr of insect feeding during 1 hr. This study concludes that both blends could be used to attract the biocontrol agent during early vegetative period of these two weeds, which could lead to eradication of weeds from rice fields.

Sulfur application enhances secretion of organic acids by soybean roots and solubilization of phosphorus in rhizosphere

ABSTRACT Nitrogen (N) fixation by rhizobia plays an important role in N assimilation of soybean (Glycine max). Nitrogenase, the enzyme responsible for N fixation in rhizobia, contains a large amount of sulfur (S) molecules and requires phosphorus (P) in adenosine triphosphate. Thus, S and P are essential for plant growth and N fixation by rhizobia. However, P in soils forms insoluble PO4 3 – salts with metals. Plant roots solubilize these PO4 3- salts by secreting organic acids and absorb solubilized PO4 3-. In this study, the effects of S application on P solubilization by soybean roots and the involvement of rhizobia were evaluated. Soybean plants inoculated with Bradyrhizobium diazoefficiens USDA110 were grown in vermiculite, and Ca3(PO4)2 was added as the sole P source. A hydroponic solution supplemented with three S concentrations (0, 20, and 1000 µM) was applied, and plants were grown for 5 weeks. Root fresh weight, the soil-plant analysis development (SPAD) values, and shoot and root S concentrations increased significantly with S application, but root nodule numbers and nitrogenase activity were not significantly affected. Organic acid secretion by roots was drastically increased by S application, and shoot P concentration and content also increased significantly. These results indicated that S application can promote P solubilization by increasing the secretion of organic acids by roots and increase in N fixation is not involved in this promotion at least in early vegetative growth period.

Do Fallow Season Cover Crops Increase N2O or CH4 Emission from Paddy Soils in the Mono-Rice Cropping System?

Cover crop management during the fallow season may play a relevant role in improving crop productivity and soil quality, by increasing nitrogen (N) and soil organic carbon (SOC) accumulation, but has the possibility of increasing greenhouse gas (GHG) emissions from the soil. A year-long consistency experiment was conducted to examine the effects of various winter covering crops on annual nitrous oxide (N2O) together with methane (CH4) emissions in the mono-rice planting system, including direct emissions in the cover crop period and the effects of incorporating these crops on gaseous emissions during the forthcoming rice (Oryza Sativa L.) growing period, to improve the development of winter fallow paddy field with covering crops and to assess rice cultivation patterns. The experiment included three treatments: Chinese milk vetch-rice (Astragalus sinicus L.) with cover crop residue returned (T1), ryegrass (Lolium multiflorum L.)-rice with cover crop residue returned (T2), and rice with winter fallow (CK). Compared with CK, the two winter cover crop treatments significantly increased rice yield, soil organic carbon (SOC) and total nitrogen (TN) by 6.9–14.5%, 0.8–2.1% and 3.4–5.4%, respectively. In all cases, the fluxes of CH4 and N2O could increase with the incorporation of N fertilizer application and cover crop residues. Short-term peaks of these two gas fluxes were monitored after all crop residues were incorporated in the soil preparation period, the early vegetative growth period and the midseason drainage period. The winter cover crop residue application greatly enhanced CH4 and N2O cumulative emissions compared with CK (by 193.6–226.5% and 37.5–43.7%, respectively) during rice growing season and intercropping period. Meanwhile, the mean values of global warming potentials (GWPs) from paddy fields with different cropping crops were T2 &gt; T1 &gt; CK. Considering the advantages of crop productivity together with environmental safety and soil quality, Chinese milk vetch-rice with cover crop residue returned would be the most practicable and sustainable cultivation pattern for the mono-rice cropping systems.

Erken gelişme döneminde yapraktan bor uygulamasının mısırın hasıl verimi ve kalitesi üzerine etkileri

Aims: This study was conducted to determine the effects of various boron quantities applied at different vegetative growth stages of maize as foliar application on hay and silage yield and quality in Southern Mediterranean ecological conditions.Methods and Results: Different boron fertilizer doses (0, 4, 6, 8 kg ha-1 disodium octaborate tetrahydrate (ETIDOT-67 (Na2B8O13.4H2O)) applied at early vegetative stages of maize (V2, V4 and V2+V4 as two portions) and the effects of boron on yield and quality prameters of maize were examined. As a result of study, higher silage and hay yields were observed at all boron applications in comparison with control and the highest yields (68.43 ton ha-1silage and 21.58 ton ha-1 hay yield) were obtained at 8 kg ha-1 boron application. Also other boron doses had the statistically similar results. Although the highest yields in terms of application times were observed at boron applications at V2+V4 stages as two portions, the differences between the application times were not statistically significant.Conclusions: We recommend that 4 kg ha-1 boron fertilizer application at early vegetative stages of maize for high silage yield and quality.Significance and Impact of the Study: Limited researches were performed on boron effects on hay and silage yields and qualities of maize up to now. This study revealed that the effects of boron application at early vegetative period of maize. Also, it is expected to be a source for further studies.

The potential of generalized additive modelling for the prediction of radial growth of Norway spruce from Central Germany

During the past decades managed forest ecosystems in Central Europe underwent vast changes, induced by extreme climate conditions and occasionally adverse forest management. Tree ring width patterns mirror these changes and thus have been widely examined as environmental archives and reliable empirical data sources in ‘tree growth modelling’. Dendrochronologists often suppose linear co-variation among the covariates, variable independence and homoscedasticity. Conventionally, these assumptions were achieved by eliminating biological age trends (detrending) and removing the autocorrelation from the time series (pre-whitening). Particularly detrending might be biased according to the scientific problem and sometimes inflexible age models. In this study, we tackle these issues and examine the suitability of a flexible Generalized Additive Model (GAM) on recently developed tree ring width time series of 30 Norway spruce stands (Picea abies [L.] H. Karst) from Central Germany.The model was established to simultaneously cope with the mentioned detrending issue, to unravel nonlinear climate-growth relationships and to predict mean ring width time series for spruce stands in the region. Particularly the latter was of primary interest, since recent forest planning relies on static yield tables that often underestimate the actual growth.The model reliably captured the empirical data, indicated by a small Generalized Cross Validation criterion (GCV = 0.045) and a deviance explained of 88.6 %. The flexible additive smoothers accounted for the social status of individual trees, captured low frequency variations of changing growth conditions adequately and displayed a rather flat biological age trend. The radial increment responded positively to summer season precipitation of the current and previous year. Positive temperature responses were found during the early vegetation period, whereas high summer season temperatures negatively affected the radial growth. The seasonal transition from spring to summer in June induced a shift in the climate response of the linear predictor, leading to a distinct negative effect of temperature and a no-role of precipitation on the linear predictor.Most important, utilizing the calibrated GAM for the purely climate-driven prediction of mean ring width time series from five independent spruce sites revealed proper coherencies. Herein, the mean ring width for sites located within the climatic-optimum for spruce growth were more exactly predicted than for sites with adverse spruce growth conditions. In addition, large mean ring widths were systematically underestimated, whereas small mean ring widths were precisely predicted. Overall, we strongly recommend GAMs as a powerful tool for the investigation of nonlinear climate-growth relationships and for the prediction of radial growth in managed forest ecosystems.

Current state of wheat insects entomofauna in Dnepropetrovsk, Zaporizhia and Poltava regions

Cereals are the basis of world crop production. In Ukraine, winter wheat crop plays a rolea strategic agricultural product. The basis of food security and the formation of the national export potential depend on this crop species. Wheat has a steadydemand on the internal and foreign markets. In the structure of crops, it occupies about 6 million hectares, which is more than 22% of all cultivated areas and almost 42% of grain crops. Like most other crops, cereals serve as food supply for a wide range of insect phytophages. Conventionally, the entire fauna of endangeredspecies can be divided into multiphages, oligophages and monophages. Cereal plants are damaged by insects during the entire growing season, from germination to harvesting. There are more than 230 species of wheat insects. Territory of the steppe zone of Ukraineamounted 17 most common and criticallyendangeredspecies on. The degree of harmfulness of each species in different vegetation periods is not the same. The goal of the paper was to reveal a current state of the most common endangeredspecies (wheat phytophages) within Dnepropetrovsk, Poltava and Zaporizhia Oblasts, and to assess a degree of their harmfulness (according to literature data). Harmful insects were accounted using conventional manual sampling method. The accounting was carried out on plots of 50 × 50 cm (0.25 m2), staggered evenly over an entire field, using a frame placed onto the plants randomly. All wheat stems inside the frame were shaken to a ground surface, and the number of harmful insects was counted. At the same time, the upper layer of soil (0–25 cm) was visually inspectedfor the presence of insect larvae and imagos. 16 samples were collectedon each field. The average number of each insect species per 1 m2 of wheat crops was calculated. As a result of 50 fields survey in Dnepropetrovsk, Zaporizhia and Poltava Oblast, a list of the most common endangeredspecies (wheat phytophages) in the steppe and forest-steppe zones was created. It includes 17 species belonging to 7 families from three orders. The most recorded representatives of Coleoptera order were 12 species, four species from Hemiptera order and one from Thysanoptera. On average, three species of wheat phytophages belong to each of the families; the largest number of endangeredspecies is represented by Scarabaeidae family. Among the identified phytophages, the most common were Harpalus rufipes (De Geer, 1774) 88% of infected fields, Zabrus tenebrioides (Goeze, 1777) 78% and Anisoplia austriaca (Herbst, 1783) 72%. Specimenof endangeredspecies as Eurygaster integriceps (Puton, 1881) were found on 34 fields, Haplothrips tritici (Kurdjumov, 1912) on 22 fields, Oulema lichenis (Heyden, 1879) on 21 fields, and Aelia acuminata (Linnaeus, 1758) on 18 fields. A brief description of each of 17 endangeredspecies was presented, taking into account their harmfulness in different periods of wheat vegetation. The degree of harmfulness of each species in different vegetation periods is not a same. A distinction is made between the early period, spring and the second half of the growing season. Early vegetation period is from the seedling emergence to the period of grass tillering. During this period, an impact of harmful insects is particularly dangerous, and a damage they cause can lead to a death of plants over large areas. The species most dangerous for wheat at this time are Harpalus rufipes and Zabrus tenebrioides. It is difficult to establish a clear distinction between the impact of endangeredspecies on plants during different periods of vegetation. With a beginning of spring vegetation, Oulema lichenis, Phyllotreta vittula and Chaetocnema aridula and Tropinota hirta are added to the above-mentioned species. Harmfulness during this period consists will be represented by leaf blade damage. The middle of vegetation coincides with an ear formation and grain filling phases. The most active endangeredwheat species during this period are considered to be Haplothrips tritici, Opatrum sabulosum, Pedinus femoralis and Blaps lethifera. The quality indicators of a cereal crop yield are reduced by Eurygaster integriceps and E. maura, Aelia acuminata and A. rostrata. Before the harvest the grain is damaged by various Scarabaeidae, in particular Anisoplia austriaca, A. agricola , A. segetum. As a result of controlling the number and species composition of endangeredwheat species, it is necessary to adapt the application of integrated methods of wheat protection to the soil and climatic conditions of the steppe and forest-steppe zones of Ukraine.

Sex Determination During Inflorescence Bud Differentiation in Monoecious Pistacia chinensis Bunge

Pistacia chinensis Bunge is widely acknowledged to be dioecious, but rare monoecious individuals have been found. However, the origin of monoecism and the sex differentiation of different sex types remain intriguing questions. Here, sex expressions were explored by identification of sex-associated DNA markers, determination of the sex stability after grafting, and histological characterization of inflorescence bud development using anatomical analysis. The results showed that (1) although polymorphisms among individuals existed, the banding patterns of Polymerase Chain Reaction (PCR) products for different sex types on the same monoecious tree were consistent; (2) the sex expressions of grafted trees were not consistent with those of scions, indicating that monoecism probably did not originate from a stable bud mutation; and (3) both males and females underwent a bisexual period, then the stamen primordia in female buds degenerated into the second round tepals, while the pistil primordia in male buds gradually disappeared. During the sex differentiation phase, female buds were spindle-shaped, while the male buds were full teardrop-shaped, and male buds were bigger than female buds. Taken together, no sex-associated DNA marker was found, sex expressions were unstable after grafting, and the alternative sex organs appeared in the early stage of sex differentiation, suggesting that sex determination occurred during floral development instead of the early vegetative period. These results indicated that the sex expressions may be affected by environmental factors, increasing the understanding of sex determination mechanisms in P. chinensis and other species.

Alternating small and large ridges with full film mulching increase linseed (Linum usitatissimum L.) productivity and economic benefit in a rainfed semiarid environment

The farming practice of alternating ridges–furrows with plastic film mulching is widely used to improve field productivity of most staple crops such as maize and wheat in the semiarid Loess Plateau, but whether the technology has similar benefits on oil crops such as linseed flax (Linum usitatissimum L.), still remains unknown. From 2012–2013, a 2–year field experiment was carried out to evaluate the effects of different ridges–furrows mulching patterns on soil hydrothermal parameters, linseed yield performance, water use efficiency and economic benefit at a rainfed semiarid site of the Loess Plateau. Four different treatments were designed as: i) alternating small and large ridges with full film mulching (RFM), ii) alternating ridges and furrows with plastic film mulching only on the ridges (RM), iii) flat planting with fully film mulching (FM) and iv) conventional flat planting without mulching (CK). Local widely cultivated variety Tianya 9 was used as testing cultivar. The results indicated that soil water storage during early growing stage was increased by 7.1%, 0.6% and 6.3% in RFM, RM and FM, respectively, compared with that of CK across two growing seasons. After harvesting, soil water storage in RFM was recovered to higher level than that of CK. Average soil temperature at seedling stage was 3.1 °C and 2.1 °C higher in RFM and FM than that of CK. In addition, film mulching generally accelerated crop development during early vegetative period, leading to a shorter growing season in RFM and RM. Particularly, both linseed yield and water use efficiency were enhanced by 116.2% and 154.8% in RFM, 50.3% and 72.4% in RM, 87.5% and 84.2% in FM across two growing seasons, respectively, compared with those of CK. Critically, the greatest net income and output to input ratio were achieved in RFM across both growing seasons. Present results clearly suggest that the practice of alternating small and large ridges with full film mulching provide an innovative option to optimize soil hydrothermal conditions, thereby boosting the productivity and profitability of dryland linseed flax in rainfed semiarid environment.

Response of white birch (Betula platyphylla Sukaczev) to temperature and precipitation in the mountain forest steppe and taiga of northern Mongolia

The mountain forest steppe and taiga in northern Mongolia have experienced a forest decline in area and quality since the end of the last century. Changes in land use, climate, fire frequency and pest occurrence are considered to be the main drivers of this vegetation shift and desertification. Because this region is the source for major rivers, is home to a unique flora and fauna and represents an important source of timber for Mongolia, the ability of different tree species to respond to these changes and regenerate is of increasing interest. Our contribution focuses on the climate-growth relationship of old and young birch trees from two valleys in the Mongolian province of Selenge Aimag.The research site Bugant, located in the Western Khentey Mountains, was the most important logging centre in Mongolia during socialist times. Today, the vegetation is dominated by succession forests of light taiga. The research site Altansumber, on the border of the Sant and Khushat soum, is dominated by light taiga and mountain forest steppe. Traditional nomads who depend on these forests for different reasons inhabit this area.Wood cores were sampled and chronologies of young and old birch trees at Bugant and Altansumber were created. Climate data were obtained from the Eroo station, which is known in the region for its long and reliable climate record. We analysed the climate-growth relationships of the chronologies from 1962 to 2009. At both sites and in both age classes, correlations with temperature were predominantly negative, particularly in April (Bugant, south- and east-facing slopes) and May (Altansumber, north-facing slopes). Precipitation of the late summer of the previous year (August/September) positively correlated with the growth of birch at Altansumber. We assume that the significant negative correlation between winter precipitation (December/January) and the growth of old birches at both sites is due to positive effects of snow cover on the survival rate of herbivorous insect populations. Our results indicate that during the early vegetation period, younger birch trees are more dependent on water availability than older ones. Negative pointer years were characterized by below-average precipitation during the current summer period and above-average spring temperatures. For the old trees, positive pointer years were characterized by above-average summer precipitation. We conclude that water availability is the most crucial factor for the growth of white birch in northern Mongolia.

Stable oxygen isotopes in juniper and oak tree rings from northern Iran as indicators for site-specific and season-specific moisture variations

Variations of stable isotopes ratios in tree rings are indicators of climate fluctuations. The current study examines the relationships between precipitation and temperature variations and stable oxygen isotopes ratios (δ18O) of the last 50 years in cellulose extracted from growth rings of Juniperus polycarpus and Quercus macranthera in northern Iran. We sampled at high-elevation sites in the Alborz Mountains, where J. polycarpus covers south-facing slopes and Q. macranthera covers north-facing slopes, respectively. δ18O values of tree-ring cellulose in oak and juniper show site-specific differences in their mean and standard deviation, but temporal variations are significantly correlated, indicating a common forcing. Correlation functions of tree-ring δ18O with local and modelled climate data reveal positive effects of temperature on δ18O values in J. polycarpus during January–June, with significant correlations in January and May. Moreover, juniper δ18O is influenced by winter precipitation, probably due to an influence of snow melt on the isotopic composition of soil water during spring. Negative correlations were found between juniper δ18O and early vegetation period precipitation, when new xylem cells are formed. In contrast, δ18O of oak contains a late summer (September) precipitation signal. Besides, δ18O values in oak are positively affected by temperatures during summer and winter, with strongest connections with temperatures of September during the previous and current growing seasons. By combining stable isotope signals of species growing under different site conditions, there is a potential to reconstruct moisture variations during different seasons in the mountain areas of north Iran.

Temperature reconstruction in the Ob River valley based on ring widths of three coniferous tree species

Tree core samples of larch (Larix sibirica Ledeb.), spruce (Picea obovata Ledeb.) and pine (Pinus sibirica Du-Tour.) from the northern taiga of West Siberia were collected to assess their potential for summer temperature reconstructions in the Ob River region. Bootstrapped response functions showed that annual growth was mainly influenced by May to June temperatures in pine and by June to July temperatures in spruce and larch. Spruce and pine chronologies showed high positive correlations with previous October temperature. June–July temperatures were reconstructed based on spruce (1795–1996) and larch (1615–1999) tree ring chronologies. The pine chronology could not be used for a reliable temperature reconstruction, due to low values of explained May–June temperature variance (11–15%) but the species has a high potential to help clarify the May–June and October climatic influence on ring width observed in all three species. We explained the effect of the early vegetation period (May–July) and the differences in the temperature signals between spruce and larch tree ring chronologies with the influence of previous September and October temperature on tree growth with the warming effect of the Ob River and differences of the species’ photosynthetic possibilities and the activity of chloroplasts and bud meristem tissues.

Desenvolvimento foliar e sincronismo dos afilhos na cultivar de arroz 'IRGA 417'

O sincronismo de emissão e desenvolvimento de folhas entre o colmo principal e afilhos é determinante para a sobrevivência dessas estruturas durante o ciclo de cultivo do arroz. O presente trabalho teve como objetivos estudar o desenvolvimento foliar do colmo principal e dos afilhos na cultivar de arroz 'IRGA 417' e identificar a ocorrência de sincronismo entre esses dois processos durante o estádio vegetativo, utilizando a escala de desenvolvimento proposta por HAUN (1973). O experimento foi conduzido em sistema hidropônico, e as plantas foram cultivadas até o início do desenvolvimento da oitava folha do colmo principal (22 dias após o transplante). A emergência da primeira folha de cada afilho foi retardada e quase coincidiu com a emissão da segunda folha. A emergência do primeiro e do segundo afilho foi concomitante e iniciou quando as plantas estavam com 3.9 unidades Haun, estendendo-se até o estádio 5.1 da escala de Haun. Já a emissão do terceiro e do quarto afilho foi posterior e ocorreu quando as plantas apresentavam, em média, 6.0 e 7.0 unidades Haun, respectivamente. O sincronismo ocorreu apesar da emissão tardia da primeira folha dos afilhos, e o percentual de afilhos sincronizados aumentou com o avanço do desenvolvimento foliar do colmo principal.

Effects of Ozone on the Growth, Yield and Leaf Gas Exchange Rates of Two Japanese Cultivars of Rice (Oryza sativa L.)

To obtain basic information concerning the evaluation of the effects of O3 on the yield of Japanese rice (Oryza sativa L.), we investigated the effects of O3 on the growth, yield and leaf gas exchange rates of rice. Two Japanese cultivars of rice (Koshihikari and Kinuhikari) were grown in plastic boxes filled with flooded Andisol in 9 chambers, and were daily exposed to charcoal-filtered air or O3 at 60 or 100 nl l-1 (ppb) (10:00-17:00) from 30 May to 20 September, 2007.The whole-plant dry mass and grain yield per plant of the two cultivars at the final harvest were significantly reduced by the exposure to O3. The reduction rates of the grain yield by the exposure to O3 at 60 and 100 ppb were 3% and 23% in Koshihikari, respectively, and 18% and 34% in Kinuhikari, respectively. The sensitivity of growth and yield to O3 was not significantly different between Koshihikari and Kinuhikari.The exposure to O3 significantly reduced the panicle number per plant, and the dry mass per panicle and filled grain number per panicle due to the increase in sterility, but did not reduce 1000 grain weight. The O3-induced reduction in the yield of the two cultivars was mainly attributed to that in the whole-plant growth during the early vegetative period and the biomass allocation to panicle during the reproductive period. During the early vegetative period, the exposure to O3 significantly reduced net photosynthetic rate and stomatal diffusive conductance, regardless of the leaf position. Therefore, the O3-induced reduction in the whole-plant growth of the two cultivars during the early vegetative period was mainly due to that in net photosynthetic rate, partially caused by the stomatal closure. Furthermore, the sensitivity to O3 of the yield components, growth parameters and leaf gas exchange rate were not significantly different between Koshihikari and Kinuhikari.

Responses of Garlic (Allium Sativum L.) to Varying Fertilization Levels and Nutrient Ratios

Garlic can be considered a typical vegetable crop in Hungary, mostly produced on relatively small family farms. Farmers often find it difficult to develop profitable production, and there are still several important questions to be solved, including effective plant protection and nutrient management. A pot experiment was carried out under greenhouse conditions to study the responses of garlic to varying fertilizer sources and nutrient ratios in 15 treatment combinations. Three increasing levels of N‐P2O5‐K2O having a ratio of 1∶0.5∶1.2 with additions of Ca, Mg, S, or CaCO3 were studied in four replicates. Three garlic cloves were planted in pots containing 2 kg of a meadow soil from southeastern Hungary (Fluvaquentic Endoaquoll) having low levels of available nutrients. Plants were grown for 191 days DAP (up to the growth stage of five to seven leaves per plant). At harvest, average plant height, fresh and dry matter (DM) production, shoot to root ratios of plants, as well as nutrient concentrations (macro‐ and microelements) were determined. From the results of the experiment, it was evident that favorable effects of plants to increasing nutrient levels could be observed. Responses of garlic showed relatively high nutrient requirements of plants at the early vegetative period. Highest DM of shoots and roots were obtained with the N3P3K3S3 treatment (226.1 and 204.6% of the control). On the other hand, higher rates of chloride had an unfavorable effect both on fresh and DM weight of plants. Nutrient concentrations also responded to variable fertilizer rates and ratios. Nitrogen concentrations showed similarities to sufficiency ranges found in literature. These values may be used for diagnostic purposes.

Far-red Light Absorbing Photoselective Plastic Films Affect Growth and Flowering of Chrysanthemum Cultivars

Growth and development responses of three chrysanthemum [Dendranthema ×grandiflora (Ramat.) Kitam. (syn. Chrysanthemum ×morifolium Ramat.)] cultivars (`Bright Golden Anne', `Iridon', and `Yellow Snowdon') to photoselective plastic films with varying concentrations (0 to 0.22 g·m-2) of a far-red (FR) light absorbing dye were investigated under greenhouse conditions. Photoselective films reduced stem elongation of all three cultivars. The greater the dye concentration in the film, the greater and earlier the reduction in stem elongation. After 4 weeks, `Yellow Snowden', `Bright Golden Anne', and `Iridon' plants grown under the film with the highest dye concentration (Afr3 film) were 21%, 26%, and 26% shorter than control plants, respectively. Height reduction under photoselective films was caused by shorter internodes. Photoselective covers were most effective in reducing the stem elongation during the early vegetative period. Following transition to the reproductive stage, weekly stem elongation rates were reduced. At the time of flowering, `Yellow Snowden', `Bright Golden Anne', and `Iridon' plants grown under the film with the highest dye concentration (Afr3 film) were 12%, 7%, and 14% short9er than control plants, respectively. Photoselective covers did not affect the anthesis of chrysanthemum cultivars, but resulted in a 10% to 14% reduction in flower diameter depending on the cultivar. Although the films with higher dye concentration were more effective in reducing stem elongation of chrysanthemum, increased dye concentration reduced light transmission. Thus, photoselective covers that reduce light transmission over 25% would not be suitable for commercial production.