Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Effects of submergence on growth and survival of saplings of three wetland trees differing in adaptive mechanisms for flood tolerance
Get PDFAim of study: Withstanding total submergence and reaeration following submergence is essential for the survival and establishment of wetland species. We focused on “LOES–low oxygen escape syndrome” and “LOQS–low oxygen quiescence syndrome” and compared tolerances to total submergence among wetland woody species differing in morphological adaptation to soil flooding.Area of study, materials and methods: This study examined the survival of 2-year-old saplings of Taxodium distichum (LOQS species), and Alnus japonica and Metasequoia glyptostroboides, (LOES species), during and after total submergence. Saplings were completely submerged, then de-submerged to determine trends in survival and growth.Main results: The M. glyptostroboides and A. japonica saplings could not survive prolonged submergence for more than 8 weeks, whereas saplings of T. distichum survived for over 2 years. Submerged saplings of all species showed no significant growth or modifications in morphology and anatomy under water, such as shoot elongation, adventitious root formation, and/or aerenchyma development. All T. distichum saplings that were de-submerged in the second year had the same pattern of shoot growth regardless of differences in timing and seasonality of de-submergence. Wood formation in T. distichum saplings ceased during submergence and resumed after de-submergence in spring and summer, but not in autumn.Research highlights: T. distichum saplings, which survived longer submergence periods than A. japonica and M. glyptostroboides, had physiological characteristics, such as suspension of growth and metabolism, which allowed survival of protracted total submergence (at least 2 years) when saplings were immersed during the dormant stage before leaf flushing.Keywords: Alnus japonica; Metasequoia glyptostroboides; survival rates; Taxodium distichum; total submergence.Abbreviations: LOES, low oxygen escape syndrome; LOQS, low oxygen quiescence syndrome
Input point distribution for regular stem form spline modeling
Get PDFAim of study: To optimize an interpolation method and distribution of measured diameters to represent regular stem form of coniferous trees using a set of discrete points.Area of study: Central-Bohemian highlands, Czech Republic; a region that represents average stand conditions of production forests of Norway spruce (Picea abies [L.] Karst.) in central Europe.Material and methods: The accuracy of stem curves modeled using natural cubic splines from a set of measured diameters was evaluated for 85 closely measured stems of Norway spruce using five statistical indicators and compared to the accuracy of three additional models based on different spline types selected for their ability to represent stem curves. The optimal positions to measure diameters were identified using an aggregate objective function approach.Main results: The optimal positions of the input points vary depending on the properties of each spline type. If the optimal input points for each spline are used, then all spline types are able to give reasonable results with higher numbers of input points. The commonly used natural cubic spline was outperformed by other spline types. The lowest errors occur by interpolating the points using the Catmull-Rom spline, which gives accurate and unbiased volume estimates, even with only five input points.Research highlights: The study contributes to more accurate representation of stem form and therefore more accurate estimation of stem volume using data obtained from terrestrial imagery or other close-range remote sensing methods.Key words: spline; stem curve; taper model; diameter position; Norway spruce
Patterns of shrub diversity and tree regeneration across topographic and stand-structural gradients in a Mediterranean forest
Get PDFAim of study: This study aimed to determine the influence of topography and stand-structure on the characteristics of shrub communities and tree regeneration in a Mediterranean forest.Area of study: The Navahondona forest in Cazorla mountain range (SE Spain).Material and Methods: Data from 298 inventory plots were analysed by means of Generalized Linear Models (GLM) to test the effects of aspect, altitude and stand basal area on shrub cover and diversity. Likewise, the effects of these three factors plus shrub cover on the recruitment of Spanish black pine (Pinus nigra spp. salzmannii) and two oak species (Quercus ilex and Q. faginea) were analysed by GLMs. Additionally, the influence of topography and forest structure on the specific distribution of shrub species was analysed with multivariate methods.Main results: Shrub cover and diversity were generally low and did not change across the topographic gradient. Tree density was the only study variable affecting (negatively) shrub cover. However, shrub composition changed with aspect and altitude. Both pine and oak regeneration benefited from partial tree cover at intermediate values of stand density, but only oak regeneration was facilitated by shrubs.Research highlights: Altitude, aspect and stand basal area influence the characteristics of shrub communities and tree regeneration. Proactive management of dense pinewoods might be needed to increase shrub and tree diversity.Key words Pinus nigra; Quercus sp.; altitude; aspect; facilitation; Shannon diversity index.
A PCR based method to detect Russula spp. in soil samples and Limodorum abortivum roots in Mediterranean environments
Get PDFAim of study. Orchidaceae has the largest number of species of any family in the plant kingdom. This family is subject to a high risk of extinction in natural environments, such as natural parks and protected areas. Recent studies have shown the prevalence of many species of orchids to be linked to fungal soil diversity, due to their myco-heterotrophic behaviour. Plant communities determine fungal soil diversity, and both generate optimal conditions for orchid development.Area of study. The work was carried out in n the two most important natural parks in Alicante (Font Roja and Sierra Mariola), in South-eastern of Spain.Material and Methods. We designed a molecular tool to monitor the presence of Russula spp. in soil and orchids roots, combined with phytosociological methods. Main results. Using a PCR-based method, we detected the presence in the soil and Limodorum abortivum orchid roots of the mycorrhizal fungi Russula spp. The species with highest coverage was Quercus rotundifolia in areas where the orchid was present.Research highlights. We present a useful tool based on PCR to detect the presence of Russula spp. in a natural environment. These results are consistent with those obtained in different studies that linked the presence of the mycorrhizal fungi Russula spp. in roots of the species Limodorum and the interaction between these fungal species and Quercus ilex trees in Mediterranean forest environments.Key words: Detection; GIS; Russula spp.; Limodorum abortivum; PCR
Effects of gap size, gap age, and bamboo Fargesia denudata on Abies faxoniana recruitment in South-western China
Get PDFAim of study: to study the effects of gap size, gap age and bamboo Fargesia denudata on natural regeneration of Abies faxoniana, both of which are the ubiquitous dominants in our research area.Area of study: subalpine coniferous forests in Wanglang Natural Reserve in Southwestern China.Material and Methods: 10 transect belts were randomly established, and a total of 97 gaps were recorded and used.Main results: (1) the number of bamboos with coverage of <17% significantly increased with increases of gap size and age, but the latter had little influence on the numbers of F. denudata with coverage of >17%. (2) F. denudata strongly inhibited A. faxoniana seedlings and saplings in small, young and old gaps, where the amount of A. faxoniana recruitment was relatively abundant, than in other types of gap. (3) The numbers of A. faxoniana seedlings in A-gaps, significantly decreased with the increases in gap size. However, in gaps where F. denudate was also present, A. faxoniana seedlings and saplings were insensitive to gap size or age. Research highlights: thick F. denudata would not be influenced by gap size or age. Because of the low occurrences of A. faxoniana seedlings and saplings, the negative effect of gap size, gap age and F. denudata on A. faxoniana recruitment was unclear.Key words: Abies faxoniana; Fargesia denudata; gap age; gap size; regeneration
Differences in the environmental control of leaf senescence of four Quercus species coexisting in a Mediterranean environment
Get PDFAims of study: Our aim is to check the effect of different environmental factors on the leaf senescence of four Quercus species with different leaf longevities, to help us better understand the implications of climate change on leaf demography.Area of study: The study was carried out in two sites of theprovince of Salamanca (central-westernSpain), both sites showing differences in their temperatures and soil water availability.Material and Methods: Over four years (2007-2010) we monitored the number of leaves of the different cohorts labelled on five specimens of each species at both sites to elaborate life-tables and calculate mortality rates. Mortality rates were then related to several other variables measured during the same period: air temperature, soil water availability, precipitation, predawn water potentials (Ypd) and leaf N resorption.Main results: In the two deciduous species maximum daily temperatures and the time during which their values remain above a certain threshold (between 11 and12ºC of maximum daily temperature) are the main factors controlling the timing of leaf abscission. In the evergreen species abscission of old leaves showed no relationship with the environmental factors analyzed. By contrast, mortality rates of old leaves were related to seasonal N resorption values, with the maximum mortality of old leaves coinciding in time with the maximum withdrawal of N from shed leaves and also with the emergence of the new leaf cohort.Research highlights: The increase in the duration of the leaves of the two deciduous species, as a result of the delayed senescence by warmer autumnal temperatures, could contribute to reducing the differences in the length of the productive leaf life with respect to the evergreen species. This could improve the competitive capacity of deciduous species as opposed to that of evergreen species, and thus alter their respective distribution patterns.Keywords: climate change; deciduous; evergreen; leaf abscission; temperature; water availability
High seed dispersal ability of Pinus canariensis in stands of contrasting density inferred from genotypic data
Get PDFAim of the study: Models that combine parentage analysis from molecular data with spatial information of seeds and seedlings provide a framework to describe and identify the factors involved in seed dispersal and recruitment of forest species. In the present study we used a spatially explicit method (the gene shadow model) in order to assess primary and effective dispersal in Pinus canariensis.Area of study: Pinus canariensis is endemic to the Canary Islands (Spain). Sampling sites were a high density forest in southern slopes of Tenerife and a low density stand in South Gran Canaria. Materials and methods: We fitted models based on parentage analysis from seeds and seedlings collected in two sites with contrasting stand density, and then compared the resulting dispersal distributions.Main results: The results showed that: 1) P. canariensis has a remarkable dispersal ability compared to other pine species; 2) there is no discordance between primary and effective dispersals, suggesting limited secondary dispersal by animals and lack of Janzen-Connell effect; and 3) low stand densities enhance the extent of seed dispersal, which was higher in the low density stand.Research highlights: The efficient dispersal mechanism of P. canariensis by wind inferred by the gene shadow model is congruent with indirect measures of gene flow, and has utility in reconstructing past demographic events and in predicting future distribution ranges for the species.Keywords: Bayesian inference; Canary Islands; gene shadow model; microsatellites; parentage analysis
Leaf blade and petiole nutritional evolution and variability throughout the crop season for Vitis vinifera L. cv. Graciano
Get PDFAn adequate nutritional state of a crop can be kept by means of a well-designed fertilization plan based on the assessment of the nutrient availability throughout the growing season. The objective of this study was to determine the reliability of leaf blade and petiole diagnosis and the period of validity of their references at both flowering and veraison by means of systematic monitoring throughout the complete growing season. The study was carried out in two plots planted with Vitis vinifera L. cv. Graciano within the AOC Rioja (Spain). Blades and petioles were collected throughout a growing season (2006) and total N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B concentrations were analyzed in both tissues. Results suggest, in general, that petioles have higher variability and lower analysis reproducibility than blades. Therefore, blade could be a more appropriate tissue to evaluate N, P, K, Ca, and Mg at both flowering and veraison in this variety. Micronutrients in blade and petiole showed different variability behaviour in each of the vineyards studied, therefore, based on our results, it was difficult to determine which one could be the best tissue for the nutritional diagnosis of the ‘Graciano’ variety. Seasonal changes of nutrient concentration in both tissues also confirmed the need for reference values for each tissue and each phenological stage
Short communication: Prediction of apparent metabolisable energy content of cereal grains and by-products for poultry from its chemical composition
Get PDF In order to predict the metabolisable energy content of ninety batches of cereal grains and cereal by-products for poultry, regression models derived from different sample aggregations and using chemical components as independent variables were compared. Several statistics have been calculated to estimate the error of prediction. The results indicate that the highest levels of significance and coefficients of determination were obtained for equations derived from the larger data sets. However, the lowest prediction errors were associated to equations calculated for data or groups of data closer to the ingredient studied
Nitrogen migration in crop rotations differing in fertilisation
Get PDFInappropriate use of nitrogen fertilisers is becoming a global problem; however, continuous fertilisation with N fertiliser ensures large and constant harvests. To evaluate the relationships of differently fertilised cultivated plant rotation with N metabolism in the agroecosystem the research was conducted between 2006 and 2013 at Lipliūnai, Lithuania, in fields with calcareous gley brown soil, i.e. Endocalcari Endohypogleyic Cambisol (CMg-n-w-can). The research area covered three drained plots where crop rotation of differently fertilised cereals and perennial grasses were applied. The greatest productivity was found in a higher fertilisation (TII, 843 kg N/ha) cereals crop rotation. With less fertilisation (TI, 540 kg N/ha) crop rotation productivity of cereals and perennial grasses (TIII, 218 kg N/ha) was 11-35% lower. The highest amount of mineral soil N (average 76 kg/ha) was found in TI. It was influenced by fertilisation (r=0.71) and crop productivity (r=0.39). TIII tended to reduce Nmin (12.1 mg/L) and Ntotal (12.8 mg/L) concentrations in drainage water and leaching of these elements (7 and 8 kg/ha). Nmin and Ntotal concentrations in the water depended on crop productivity respectively (r=0.48; r=0.36), quantity of mineral soil N (r=0.65; r=0.59), fertilisation (r=0.59; r=0.52), and N balance (r=0.26; r=0.35). Cereal crop rotation increased N leaching by 12-42%. The use of all crop rotations resulted in a negative N balance. Nitrogen balance depended on fertilisation with N fertiliser (r=0.55). The application of perennial grasses crop rotation in agricultural fields was the best environmental tool, reducing N migration to drainage