Pirjo Peltonen-Sainio

Uptake and translocation of foliar-applied glycinebetaine in crop plants

Abstract Glycinebetaine is known as an osmoprotectant which is accumulated in certain plant species under salt and drought stresses. Exogenous applications of glycinebetaine on crop plants unable to synthesise glycinebetaine is a possible approach to overcome the environmental limitations of crop production. Information about the capability of plants to take up and translocate foliar-applied glycinebetaine is, however, limited. In this study, glycinebetaine solution, with and without surfactants, was exogenously applied to foliage of summer turnip rape (Brassica rapa L. ssp. oleifera), soybean [Glycine max (L.) Merr.], pea (Pisum sativum L.), tomato (Lycopersicon esculentum Mill.), and spring wheat (Triticum aestivum L.) in greenhouse experiments. Uptake of glycinebetaine was monitored using high-performance liquid chromatography. [14C]glycinebetaine was applied to leaves of turnip rape plants and translocation to other plant organs was monitored autoradiographically. [14C]glycinebetaine was translocated to roots within two hours of application. One day after application labelled glycinebetaine was translocated to all plant parts of turnip rape plants. The results indicate that plants are able to translocate foliar-applied glycinebetaine from their leaves to other organs, and that the use of surfactants accelerates the penetration of foliar-applied glycinebetaine. According to our results glycinebetaine is quite inert end-product in plant cells being mainly phloem-mobile. Moreover, environmental conditions are shown to affect the uptake and translocation rates of foliar-applied glycinebetaine.

Climate change and prolongation of growing season: changes in regional potential for field crop production in Finland

Climate change offers new opportunities for Finnish field crop production, which is currently limited by the short growing season. A warmer climate will extend the thermal growing season and the physiologically effective part of it. Winters will also become milder, enabling introduction of winter-sown crops to a greater extent than is possible today. With this study we aim to characterise the likely regional differences in capacity to grow different seed producing crops. Prolongation of the Finnish growing season was estimated using a 0.5o latitude × 0.5o longitude gridded dataset from the Finnish Meteorological Institute. The dataset comprised an average estimate from 19 global climate models of the response of Finnish climate to low (B1) and high (A2) scenarios of greenhouse gas and aerosol emissions for 30-year periods centred on 2025, 2055 and 2085 (Intergovernmental Panel on Climate Change). Growing season temperature sums that suit crop growth and are agronomically feasible in Finland are anticipated to increase by some 140 °Cd by 2025, 300 °Cd by 2055 and 470 °Cd by 2085 in scenario A2, when averaged over regions, and earlier sowing is expected to take place, but not later harvests. Accordingly, the extent of cultivable areas for the commonly grown major and minor crops will increase considerably. Due to the higher base temperature requirement for maize (Zea mays L.) growth than for temperate crops, we estimate that silage maize could become a Finnish field crop for the most favourable growing regions only at the end of this century. Winters are getting milder, but it will take almost the whole century until winters such as those that are typical for southern Sweden and Denmark are experienced on a wide scale in Finland. It is possible that introduction of winter-sown crops (cereals and rapeseed) will represent major risks due to fluctuating winter conditions, and this could delay their adaptation for many decades. Such risks need to be studied in more detail to estimate timing of introduction. Prolonged physiologically effective growing seasons would increase yielding capacities of major field crops. Of the current minor crops, oilseed rape (Brassica napus L.), winter wheat (Triticum aestivum L.), triticale (X Triticosecale Wittmack), pea (Pisum sativum L.) and faba bean (Vicia faba L.) are particularly strong candidates to become major crops. Moreover, they have good potential for industrial processing and are currently being bred. Realisation of increased yield potential requires adaptation to 1) elevated daily mean temperatures that interfere with development rate of seed crops under long days, 2) relative reductions in water availability at critical phases of yield determination, 3) greater pest and disease pressure, 4) other uncertainties caused by weather extremes and 5) generally greater need for inputs such as nitrogen fertilisers for non-nitrogen fixing crops.

Foliar application of glycinebetaine—a novel product from sugar beet—as an approach to increase tomato yield

Abstract Glycinebetaine, a novel product from sugar beet (Beta vulgaris L. v. altissima), is purified from molasses during sugar processing through chromatographic separation, enrichment and crystallisation. Glycinebetaine is environmentally safe, non-toxic and water-soluble and is found in animal, microbe and plant cells. Most halophytes, when grown under stress, synthesise glycinebetaine in their chloroplasts and accumulate it as an osmoprotectant. Here we show that foliarly applied glycinebetaine offers a new possibility to stabilise crop production under field conditions: fruit yield of tomato plants (Lycopersicon esculentum Mill.) grown in saline soils or exposed to high temperatures in California increased up to 39% when glycinebetaine was applied during midflowering. Similarly, glycinebetaine treatment of tomato plants in a commercial vegetable producers greenhouse in Southern Finland increased the yield and the number of tomato fruits. In a separate greenhouse experiment, we showed that glycinebetaine application increased the rate of net photosynthesis of adequately watered and salt stressed tomato plants.

Changes in time of sowing, flowering and maturity of cereals in Europe under climate change

The phenological development of cereal crops from emergence through flowering to maturity is largely controlled by temperature, but also affected by day length and potential physiological stresses. Responses may vary between species and varieties. Climate change will affect the timing of cereal crop development, but exact changes will also depend on changes in varieties as affected by plant breeding and variety choices. This study aimed to assess changes in timing of major phenological stages of cereal crops in Northern and Central Europe under climate change. Records on dates of sowing, flowering, and maturity of wheat, oats and maize were collected from field experiments conducted during the period 1985–2009. Data for spring wheat and spring oats covered latitudes from 46 to 64°N, winter wheat from 46 to 61°N, and maize from 47 to 58°N. The number of observations (site–year–variety combinations) varied with phenological phase, but exceeded 2190, 227, 2076 and 1506 for winter wheat, spring wheat, spring oats and maize, respectively. The data were used to fit simple crop development models, assuming that the duration of the period until flowering depends on temperature and day length for wheat and oats, and on temperature for maize, and that the duration of the period from flowering to maturity in all species depends on temperature only. Species-specific base temperatures were used. Sowing date of spring cereals was estimated using a threshold temperature for the mean air temperature during 10 days prior to sowing. The mean estimated temperature thresholds for sowing were 6.1, 7.1 and 10.1°C for oats, wheat and maize, respectively. For spring oats and wheat the temperature threshold increased with latitude. The effective temperature sums required for both flowering and maturity increased with increasing mean annual temperature of the location, indicating that varieties are well adapted to given conditions. The responses of wheat and oats were largest for the period from flowering to maturity. Changes in timing of cereal phenology by 2040 were assessed for two climate model projections according to the observed dependencies on temperature and day length. The results showed advancements of sowing date of spring cereals by 1–3 weeks depending on climate model and region within Europe. The changes were largest in Northern Europe. Timing of flowering and maturity were projected to advance by 1–3 weeks. The changes were largest for grain maize and smallest for winter wheat, and they were generally largest in the western and northern part of the domain. There were considerable differences in predicted timing of sowing, flowering and maturity between the two climate model projections applied.

An evaluation of the effect of exogenous glycinebetaine on the growth and yield of soybean: timing of application, watering regimes and cultivars

Various soybean cultivars were grown under different watering regimes in the field and greenhouse in south-eastern U.S.A. (1995 and 1996), and in the field in north-eastern Western Australia (1995). Aqueous glycinebetaine was applied at different growth stages onto their foliage with the objective of ameliorating effects of water stress on photosynthesis activity, nitrogen fixation, leaf growth, biomass accumulation and seed yield. There were cultivar differences in response to drought. Trends which suggest that exogenous glycinebetaine could improve photosynthesis activity, nitrogen fixation and leaf area development, were established. The observed seed yield increase of both well-watered and drought-stressed plants was associated with greater number of seeds following the application of 3 kg ha−1 glycinebetaine. The results indicate that foliar-applied glycinebetaine possesses anti-transpirant properties and has the potential to improve drought tolerance and reduce the amount of water used for irrigation, without any significant decrease in economic yield. There is evidence that soybean could be classified as a low-accumulator of glycinebetaine.

Variation in harvest index of modern spring barley, oat and wheat cultivars adapted to northern growing conditions

Increased harvest index (HI) has been one of the principal factors contributing to genetic yield improvements in spring barley ( Hordeum vulgare L.), oat ( Avena sativa L.) and wheat ( Triticum aestivum L.) cultivars. Although high HI demonstrates high-yielding ability when cultivars are compared, it can also indicate challenges to yield formation when comparisons are made across differing growing conditions. The present study was designed to investigate variation in HI among modern cereal cultivars relative to that brought about by a northern environment, to assess whether HI still explains the majority of the differences in grain yield when only modern cereal cultivars are compared, and to monitor key traits contributing to HI. Stability of HI was also investigated with reference to the role of tillers. Twelve experiments (3 years, two locations, two nitrogen fertilizer regimes) were carried out in southern Finland to evaluate 12 two-row spring barley, 10 six-row barley, 10 oat and 11 wheat cultivars. In addition to HI, days to heading and maturity, length of grain filling period, grain yield, test weight and 13 traits characterizing plant stand structure were measured and analysed with principal component analysis (PCA) to detect traits associated with HI and those contributing to stability of HI. Although only modern cereals were studied, differences among cultivars were significant both in mean HI and stability of HI, and HI was associated with short plant stature in all modern cereal species. Also, single grain weight was associated with HI in all species. Differences between, but not within, species in HI were partly attributable to differences in tiller performance. Grain yield was associated closely with HI except in two-row barley. It may be possible to further increase HI of wheat, as it still was relatively low. High HI did, however, not indicate the degree of success in yield determination when environments are compared.

Shifts in comparative advantages for maize, oat and wheat cropping under climate change in Europe

Climate change is anticipated to affect European agriculture, including the risk of emerging or re-emerging feed and food hazards. Indirectly, climate change may influence such hazards (e.g. the occurrence of mycotoxins) due to geographic shifts in the distribution of major cereal cropping systems and the consequences this may have for crop rotations. This paper analyses the impact of climate on cropping shares of maize, oat and wheat on a 50-km square grid across Europe (45–65°N) and provides model-based estimates of the changes in cropping shares in response to changes in temperature and precipitation as projected for the time period around 2040 by two regional climate models (RCM) with a moderate and a strong climate change signal, respectively. The projected cropping shares are based on the output from the two RCMs and on algorithms derived for the relation between meteorological data and observed cropping shares of maize, oat and wheat. The observed cropping shares show a south-to-north gradient, where maize had its maximum at 45–55°N, oat had its maximum at 55–65°N, and wheat was more evenly distributed along the latitudes in Europe. Under the projected climate changes, there was a general increase in maize cropping shares, whereas for oat no areas showed distinct increases. For wheat, the projected changes indicated a tendency towards higher cropping shares in the northern parts and lower cropping shares in the southern parts of the study area. The present modelling approach represents a simplification of factors determining the distribution of cereal crops, and also some uncertainties in the data basis were apparent. A promising way of future model improvement could be through a systematic analysis and inclusion of other variables, such as key soil properties and socio-economic conditions, influencing the comparative advantages of specific crops.

Seeding rate effects on tillering, grain yield and yield components of oat at high latitude

Abstract A seeding rate for oat (Avena sativa L.) of 500 viable seeds m−2 is used in Finland for development of a uniculm stand, and to avoid post-anthesis tillering and subsequent uneven ripening of the crop. Plant breeding has, however, considerably altered plant height and plant stand structure, thereby possibly changing tillering capacity. The objective of this study was to assess the contribution of tillers to grain yield and morpho-physiological traits comparing an oat landrace cultivar (Jalostettu maatiainen), a modern cultivar (Puhti), and a semi-dwarf line (Hja 76416) when grown at 200 to 900 viable seeds m−2 at increments of 100 seeds m−2. The experiments were conducted at Viikki Experimental Farm, University of Helsinki, Finland (60°13′N), in 1991 and 1992. Increasing the seeding rate significantly increased the number of main culms m−2, but decreased straw length and several yield components on the main shoot. Tillers in the semi-dwarf line contributed 27% to the grain yield at 200 seeds m−2. This line yielded highest at 600 seeds m−2 which favored a uniculm growth habit, and 98% of grain yield was solely from main panicles. Due to the sensitivity of the landrace and modern cultivar to lodging, no significant effect of seeding rate on grain yield was recorded under favorable growing conditions (1991). The highest grain yield for them was recorded at 600 to 800 seeds m−2 with early summer drought (1992). No tiller contribution to grain yield was observed at ⩾ 500 seeds m−2. Following sensitivity to lodging the optimum seeding rate for the longer strawed lines is lower and more dependent on environmental factors than that for the semi-dwarf line.

EFFECT OF FOLIAR APPLICATION OF GLYCINEBETAINE ON YIELD COMPONENTS OF DROUGHT-STRESSED TOBACCO PLANTS

Two glasshouse experiments were conducted at the Department of Plant Production, University of Helsinki, Finland, to study the effect of foliar application of aqueous 0.1 and 0.3M glycinebetaine on leaf growth of drought-stressed tobacco (Nicotiana tabacum L.) cv. Samsun. Leaf nitrogen and glycinebetaine concentrations were estimated periodically. After 16 days of treatment, leaves were harvested, and fresh and dry weights, and area determined. The number of total and green leaves was also recorded. Significant increases in leaf fresh and dry weights, and area were associated with glycinebetaine application, especially when drought was induced early. The application of 0.3M glycinebetaine reduced leaf area duration. Residual leaf glycinebetaine content remained high 16 days after application. The results indicate that exogenous glycinebetaine has the potential to improve the drought tolerance of leaf tobacco.

Characterization of variation in the lignan content and composition of winter rye, spring wheat, and spring oat.

To characterize the range of variation in lignan content and composition caused by genotype and environment, seven dietary lignans, i.e., 7-hydroxymatairesinol, secoisolariciresinol, matairesinol, lariciresinol, pinoresinol, medioresinol, and syringaresinol, were analyzed by high-performance liquid chromatography-tandem mass spectrometry in whole-grain extracts of cereal samples collected at eight locations in Finland. In all, 28 winter rye, 73 spring wheat, and 55 spring oat samples were analyzed, representing 6, 9, and 5 cultivars, respectively. The total lignan content showed huge variations within the same cereal species: the range was 2500-6700 microg/100 g in the rye samples, 340-2270 microg/100 g in the wheat samples, and 820-2550 microg/100 g in the oat samples. The variations seemed to depend largely upon genetic differences. In rye, also environmental conditions affected the lignan content through grain size; smaller grains had significantly lower total lignan, syringaresinol, and lariciresinol content than larger grains. This study shows that varying cereal lignan concentrations reported in different studies may be, besides differences in analytical methods, largely dependent upon natural variations.