冷湿层积法对印度冷杉(Abies pindrow)和长叶云杉(Picea smithiana）种子萌发的影响

研究赤霉素(GA3),冷湿和温度 对五个种源的印度冷杉(Abies pindrow)和长叶云杉(Picea smithiana)种子萌发的影响.种子被浸泡在GA3 (10 mg(L-1)中24小时,然后在3(5(C温度的条件下冷藏15天.设计4个温度(10(C, 15(C, 20(C 和 25(C)条件来促进种子的萌发.结果表明,浸泡和冷湿处理明显增加种子的萌发率.在10 (C时种子的萌发率最高.总体结果表明,种子被浸泡在GA3 (10 mg(L-1)中24小时,冷湿藏15天,可以有效地促进印度冷杉和长叶云杉的种子萌发.统计数据表明,浸泡处理、温度和种源以及与温度的相互作用都对种子的萌发有明显的影响.     

Three-year storage of oriental beechnuts (<Emphasis Type="Italic">Fagus orientalis</Emphasis> Lipsky)

Oriental beech (Fagus orientalis) is one of the main tree species in Turkey. In this study, 3-year storage of oriental beechnuts from eight Turkish provenances was researched. Beechnuts were stored at −6°C in sealed containers. The average germination percentages of over all provenances were 91.67, 75.92, and 76.75%, prior to initial storage, after 1 year in storage, and after 3 years in storage, respectively. There were significant decreases in the germination percentages of seven provenances while one provenance retained its high initial germination ability over a 3-year storage period. The loss of viability initiated from the radicle and the plumula in stored beechnuts. The average mean germination times were 10.43, 10.22, and 11.89 weeks prior to storage, after 1 year in storage, and after 3 years in storage, respectively. The beechnuts stored for 3 years germinated significantly later than both fresh beechnuts and beechnuts stored for 1 year in terms of average mean germination time. This study showed that oriental beechnuts can be stored in a dormant state for at least 3 years at low temperature (−6°C) with a low moisture content (about 6–7%).     

Laboratory evaluation of five novel pyrrole derivatives as grain protectants against <Emphasis Type="Italic">Tribolium confusum</Emphasis> and <Emphasis Type="Italic">Ephestia kuehniella</Emphasis> larvae

Several naturally discovered or laboratory-synthesized pyrrole compounds have insecticidal, acaricidal and microbial properties. The novel sulfanyl 5H-dihydro-pyrrole derivatives exhibit certain antioxidant activities. However, there is a knowledge gap whether these substances are potent grain protectants against stored-product insect pest species. In this context, we evaluated the insecticidal activity of five novel pyrrole derivatives (under the trivial names 3a, 3g, 3l, 3m, 3h), against larvae of Tribolium confusum Jaquelin du Val and Ephestia kuehniella Zeller at different doses (0.1, 1 and 10 ppm), exposure intervals (7, 14 and 21 days or 1, 2, 7, 14, 21 days), temperatures (20, 25 and 30 °C), relative humidity (RH) (55 and 75 %) levels and commodities (wheat, maize, barley). The pyrrole derivative 3a exhibited the highest insecticidal activity, while 3g, 3l, 3m and 3h caused similar mortality against larvae of T. confusum. Apart of the level of efficacy, all tested pyrrole derivatives performed similarly according temperature. We found that increase in temperature increased mortality in the majority of the tested combinations. Generally, the pyrrole derivatives caused the highest mortality levels at 30 °C. The pyrrole derivatives 3a, 3g, 3l and 3m were affected by relative humidity at almost all combinations tested. The 75 % level of RH moderated the efficacy of the pyrrole derivatives, while the 55 % enhanced it. Mortality of T. confusum and E. kuehniella on maize was much lower on treated maize than barley or wheat. However, 100 % control of both species was recorded only on treated barley. The results of the present study indicate that the pyrrole derivatives tested could serve as grain protectants against noxious stored-product insects under certain biotic and abiotic conditions.     

Variability in cone and seed characteristics and seed testing in various provenances of Himalayan spruce (<Emphasis Type="Italic">Picea smithiana</Emphasis>)

We investigated the effect of provenance variation on cone and seed morphology and germination behaviour under different pre- treatments in Picea smithiana. Three categories of cones were recognized: large (13.18 cm × 3.30 cm 15.42 cm × 4.35 cm), medium (10.85 cm × 3.93 cm 12.18 cm × 3.98 cm) and small (7.69 cm × 3.06 10.98 cm× 3.39 cm). Significant variation was observed for various cone and seed characteristics. Seeds moisture content varied from 44.48% to 56.91%, seed size from 0.64 cm × 0.31 cm (largest seed) to 0.49 cm × 0.10 cm (smallest seed), and the seed weight from 2.45 g per 100 seeds to 1.36 g per 100 seeds on fresh weight basis of P. smithiana. The highest seed germination (72.0±7.53%) at 10°C was observed under chilling treatment in Tapovan provenance, while the minimum (15.0±5.71%) seed germina- tion was recorded at 25°C under control set in Tapovan provenance. Further among all the sources Pandukeshwar consistently had the highest average (38%) percent germination across all treatments. Compared to other temperature regimes and pretreatments, seeds subjected to 10°C and chilling treatment had the highest germination and took the least time for germination irrespective of provenance effects. Altitude (provenance) had little or no relationship with germination following laboratory treat- ments. Seeds from Tapovan provenance subjected at 10°C following chilling treatment may be suggested for further multiplication of this species.     

Efficacy of low temperatures for the control of all life stages of <Emphasis Type="Italic">Plodia interpunctella</Emphasis> and <Emphasis Type="Italic">Liposcelis bostrychophila</Emphasis>

The insecticidal effect of low temperatures for the control of all life stages of two stored-product insects, Plodia interpunctella and Liposcelis bostrychophila, was evaluated under laboratory conditions. The temperatures tested were 0, ??5, ??10 and ??15 °C, and, at these temperatures, the insects were exposed for 2, 4 and 8 h and also for 1, 2, 3 and 7 days. Regarding P. interpunctella, the most cold-tolerant life stage was larvae, given that 2 days of exposure were needed for complete (100%) mortality at ??10 °C. Moreover, all larvae were dead at ??15 °C even after 2 h of exposure. Eggs of P. interpunctella were susceptible to cold, as mortality was complete after 7, 1 day, 2 and 2 h at 0, ??5, ??10 and ??15 °C, respectively. L. bostrychophila was by far less susceptible than P. interpunctella. For this species, adults were still alive even after 7 days at ??10 °C, while complete mortality was achieved only after 1 day at ??15 °C. Eggs of L. bostrychophila were the most cold-tolerant life stage, as survival was observed even after 3 days at ??15 °C. The results of the present study provide the first data set on which all life stages of P. interpunctella and L. bostrychophila are evaluated for their susceptibility to cold treatments in a standardized series of exposures and temperatures. These results are expected to further encourage the “real world” application of cold treatments for the disinfestation of durable stored-products.     

Variation in seed traits and seedling vigour of <Emphasis Type="Italic">Cordia africana</Emphasis> Lam. provenances in Ethiopia

Cordia africana is a very important indigenous tree species for timber and other products and services in Ethiopia. Seed traits and seedling vigour of seeds from 12 provenances of the species were compared. Mean seed mass for each provenance was assessed for 1000 seeds in 10 replications, and seed length and width were measured for 100 seeds in four replications per provenance. Germination was assessed in a glasshouse taking 400 seeds from each provenance. Root collar diameter and height of 440 seedlings grown in a nursery for 290 days in Addis Ababa were measured. Seed length, seed width, seed mass, and shoot height and root collar diameter of seedlings showed significant differences (P < 0.001) among provenances. Correlation analysis between seed and seedling traits and environmental variables revealed significant positive correlations between seed width and germination percentage, seed width and altitude, seed width and longitude and seed length and latitude. Negative correlations were obtained between seed width and temperature, seed width and rainfall, seed mass and temperature, and germination and temperature of the seed source. As expected, differences in seed trait did not explain the variability in seedling vigour. Determining quantitative variations in seed traits and seedling vigour among provenances and the patterns along environmental gradients are essential for informing decisions on the tree improvement programme of the species.     

Diapause termination,developmental threshold and thermal requirements of eggs of the maple aphid,<Emphasis Type="Italic">Periphyllus californiensis</Emphasis> Shinji

The lower developmental threshold and thermal requirements for egg hatch of the maple aphid (Periphyllus californiensis) were estimated to be 4.58°C and 94.48 degree-days. Eggs of the maple aphid appear to have obligatory diapause and chilling seems essential for diapause development. No matter whether eggs in diapause were treated with 2°C chilling or placed in the field, at least 35 to 41 days were required for the first egg to terminate diapause. The time of egg hatch lasted for about a month or even longer. This long period of time in egg hatch may be related to the restricted period that food is available in early spring and the long period of budburst of host plants.     

Provenance and pretreatment effect on seed germination of six provenances of <Emphasis Type="Italic">Faidherbia albida</Emphasis> (Delile) A. Chev

A nursery experiment was conducted to determine the effects of seed pretreatment methods on the germination of Faidherbia albida at ICRAF, Nairobi from six provenances consisting of Awassa, Taveta, Lake Koka, Maseno, Chinzombo and Wagingombe. Seeds were subjected to five pretreatment methods namely nicking, soaking in acid, hot water, cold water and control. Germination percentages (GP), mean germination time (MGT) and germination index (GI) were calculated and the data was subjected to ANOVA. The study revealed significant (p ≤ 0.05) differences in seed treatments among provenances in all studied parameters. Highest germination among pretreatments in Awassa (99 %) and Wagingombe (80 %) was observed in nicked seeds, Chinzombo (81 %) in nicked and acid treated seeds, Lake Koka (90 %) in acid treated seeds and Taveta (28 %) and Maseno (64 %) in cold water treated seeds. Nicking gave the highest cumulative GP (69.67) while lowest GP was observed in hot water treated seeds (23.17). Acid treatment exhibited lowest MGT (8.85 days) and highest GI (2.29) while highest MGT (24.35 days) and lowest GI (0.31) were observed in control and hot water treatment respectively. Although acid treatment gave a high GP and lowest MGT and GI, nicking and soaking in cold water for 24 h is being recommended as cheaper and less hazardous pretreatment methods to improve germination in F. albida since sulphuric acid is expensive and requires proper handling techniques. Significant correlation between geo-climatic data and germination parameters of seeds subjected to different pretreatments indicates that provenances are as important as pretreatments in germination of the species.     

Late frost sensitivity of juvenile <Emphasis Type="Italic">Fagus sylvatica</Emphasis> L. differs between southern Germany and Bulgaria and depends on preceding air temperature

Fagus sylvatica, the dominant native forest tree species of Central Europe, is sensitive to late frost events. Advanced leaf flushing due to climate warming may lead to more frequent frost damage in the future. Here, we explore local adaptation to late frost events at both continental and regional scales and test how moderate climate warming (+1.5°C) affects late frost sensitivity. Short-term leaf injury and height growth after a late frost event were quantified in a common garden experiment with 2-year-old F. sylvatica seedlings. The fully crossed three-factorial design consisted of a late frost manipulation, a continuous warming manipulation and selected provenances (three provenances from western Bulgaria and three from southern Germany). Late frost led to leaf injury and reduced height growth (−7%). Provenances differed in their late frost sensitivity at the regional scale, and local adaptation was detected. At the larger scale, the Bulgarian provenances showed reduced height growth (−17%), while the German provenances did not exhibit growth reduction. The warming treatment prevented late frost damage, while height growth declined by 19% in the reference temperature treatment. This surprising finding was attributed to advanced leaf maturity in the warming treatment. The impact of late frost events on F. sylvatica in a warmer world will depend on timing. An event that damages leaves immediately after leaf flushing appears negligible a few days earlier or later, thereby complicating projections. Local adaptation to late frost is evident at a regional scale. Management strategies should aim at maximizing genetic diversity to adapt to climate change.     

Adaptation to common optimum in different populations of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> Karst.)

Responses of Norway spruce populations to climatic transfer, in terms of growth and survival, were analyzed on the basis of a provenance experiment derived from the international provenance test IUFRO 1964/1968. The experiment comprises a series of five trial plots situated at contrasting elevations ranging from 484 to 1,275 m a.s.l., with 11 provenances represented at all trial plots that were used for the analysis. Transfer rates were defined as differences in altitudes or climatic variables between the site of plantation and the site of origin. Optimal transfer rates and optimal climates for individual provenances were derived from quadratic response functions. Spruce provenances generally responded positively by height and volume growth to transfer into lower altitudes, i.e., warmer conditions with less precipitations. The analysis at the level of provenances showed that optimal transfer rates were consistently negatively correlated with the underlying environmental variables and optimal climates were consequently nearly the same for all provenances irrespective of the response traits and ecodistance variables. Stability indices based on joint regression analysis indicate that provenances from higher altitudes, colder and wetter climates tend to be more stable, whereas provenances from lower altitudes, drier and warmer sites are more responsive to site quality. However, the differences in the stability are small and stability indices were generally close to 1. The results indicate that populations in different climates remain adapted to a common optimum and the extent of local adaptation is quite limited. Possible explanations of this observation are briefly discussed.     

Application of near infrared spectroscopy for authentication of <Emphasis Type="Italic">Picea abies</Emphasis> seed provenance

Authentication of seed provenance is an importance issue to avoid the negative impact of poor adaptation of progenies when planted outside their natural environmental conditions. The objective of this study was to evaluate the potential of near infrared (NIR) spectroscopy as rapid and non-destructive method for authentication of Picea abies L. Karst seed provenances. For this purpose, five seed lots from Sweden, Finland, Poland and Lithuania each were used. NIR reflectance spectra were recorded on individual seeds (n = 150 seeds × 5 seed lots × 4 provenances = 3000 seeds) using XDS Rapid Content Analyzer from 780 to 2500 nm with a resolution of 0.5 nm. Classification model was developed by orthogonal projection to latent structures-discriminant analysis. The performance of the computed classification model was validated using two test sets—internal (the same seed lots as the model but excluded during model development; n = 600 seeds) and external (seed lots not included in the model; n = 1158 seeds). For the internal test, the model correctly recognized 99% of Swedish, Finnish and Polish samples and 97% of Lithuanian seeds. For the external test samples, the model correctly assigned 81% of Swedish, 96% of Finnish, 98% of Lithuanian and 93% of Polish seeds to their respective classes. The mean classification accuracy was 99 and 95% for internal and external test set, respectively. The spectral differences among seed lots were attributed to differences in chemical composition of seeds, presumably fatty acids and proteins, which are the dominant storage reserves in P. abies seeds. In conclusion, the results demonstrate that NIR spectroscopy is a very promising method for monitoring putative seed provenances and in seed certification.     

Fumigant activity of <Emphasis Type="Italic">Illicium verum</Emphasis> fruit extracts and their effects on the acetylcholinesterase and glutathione<Emphasis Type="Italic"> S</Emphasis>-transferase activities in adult <Emphasis Type="Italic">Sitophilus zeamais</Emphasis>

The insecticidal activity of Illicium verum Hook. f. against Sitophilus zeamais Motschulsky adults were identified, and the underlying mechanisms were studied. Extracts from I. verum fruits in methyl alcohol (MA), ethyl acetate (EA), and petroleum ether (PE) were tested by fumigation in a hermetic container to determine their toxicity. The effects of the three extracts on the activity of acetylcholinesterase (AChE) and glutathione S-transferases (GSTs) of S. zeamais were determined in vivo. All extracts showed strong fumigant activity. The fumigant effects were enhanced with increased dosage and prolonged exposure time. 1.25, 2.50, 5.00, 10.00, and 20.0 mg/l doses of the MA, EA, and PE extracts caused the mortalities from 8.37 to 90.26 %, 21.81 to 95.89 %, and 15.84 to 92.57 %, respectively, at 72 h after treatment. Consequently, the most effective dose of the MA, EA, and PE extracts is the 20.0 mg/l. The LD₅₀ of the MA, EA, and PE extracts at 72 h after treatment were 7.10, 3.93, and 4.55 mg/l, respectively. The activities of AChE and GSTs were notably inhibited by the three extracts, as compared with the control, with strong dose- and time-dependent effects. The inhibition strength of the three extracts on AChE and GSTs activities were in the following order: EA extract > PE extract ≥ MA extract. Therefore, I. verum extracts could be explored as novel natural fumigants for the future control of stored-product insect pests.     

Osmoregulators in <Emphasis Type="Italic">Hymenaea courbaril</Emphasis> and <Emphasis Type="Italic">Hymenaea stigonocarpa</Emphasis> under water stress and rehydration

The objective of this work was to evaluate the effect of different water deficiency and rehydration levels on the concentrations of osmoregulators in two plant species (Hymenaea courbaril and H. Stigonocarpa) in the Amazon. We adopted a 2 × 5 × 5 factorial system, referring to 2 species (H. courbaril and H. stigonocarpa) and 5 stages of hydration and rehydration. The five hydration and rehydration stages were established in: (1) Control treatment E0; (2) Plants with 13 days of stress after incubation—E13; (3) Plants with 26 days of stress E26; (4) The plants that were established after 26 days after incubation and rehydrated for two days (RD2); (5) rehydrated for two days (RD4). The plants that were established after 26 days after incubation and rehydrated for four days. The experiment totaled fifty young plants with five replicates. Biochemical measurements were performed at the beginning of the experiment (E0) at 13 (E13) and 26 (E26) days after the water stress, in which the plants were rehydrated, repeating the analyses after two (RD2) and four (RD4) days. Both species increased the sucrose concentration by 18%, with a decrease of 52% in starch content. The RD4 time presented the highest mean starch concentration (0.19 mmol g^?1 of the residue for H. courbaril and 0.27 mmol g^?1 of residue for H. stigonocarpa). Increased proline concentrations were recorded for controls until RD2 for both species. For glycine betaine, the highest increases in treatments E26 and RD2 were observed for the H. courbaril species. Our rehydration period was not sufficient for total recovery of pre-stress concentrations of all studied solutes.     

Shoot multiplication of <Emphasis Type="Italic">Syringa reticulata</Emphasis> var. <Emphasis Type="Italic">mandshurica</Emphasis> from in vitro cultured seedlings

We developed a shoot multiplication protocol for Syringa reticulata Blume var. mandshurica Hara from in vitro cultured seedlings that derived from in vitro germinated seeds. The shoots could be induced on Murashige and Skoog (MS) medium with proper plant growth regulator combinations of 6-benzylaminopurine (BA) and indole-3-butyric acid (IBA). The better medium for shoot multiplication and growth was MS + 5 mg L^?1 BA + 0.5 mg L^?1 IBA + 20 g L^?1 sucrose + 7 g L^?1 agar, and the corresponding shoot induction rate was 75 %. The plantlets grew well after rooting on 1/2MS medium (macro-elements of MS medium are at half-strength) supplemented with 1 mg L^?1 IBA, and the survival percentage was >80 % at 16 weeks after transplanting.     

Litterfall,decomposition and nutrient release of <Emphasis Type="Italic">Shorea robusta</Emphasis> and <Emphasis Type="Italic">Tectona grandis</Emphasis> in a sub-tropical forest of West Bengal,Eastern India

We studied leaf litter fall, decomposition and nutrient release patterns of Shorea robusta and Tectona grandis by using a litter bag technique to better understand the release pattern of nutrients to soil from leaf litter. Annual litterfall varied from 13.40 ± 2.56 t ha^?1 a^?1 for S. robusta to 11.03 ± 3.72 t ha^?1 a^?1 for T. grandis and the decay constant (k) of decomposed leaf litter was distinctly higher for T. grandis (2.70 ± 0.50 a^?1) compared to S. robusta (2.41 ± 0.30 a^?1). Biomass loss was positively correlated with the initial litter C, WSC, C/N and ash content in S. robusta and N, P and K concentration for T. grandis. Biomass was negatively correlated with lignin and L/N ratio for S. robusta and L, WSC, L/N and C/N ratio for T. grandis (P < 0.01). Nutrient use efficiency (NUE) and nutrient accumulation index (NAI) of S. robusta was higher than for T. grandis. The retranslocation of bioelements from senescent leaves ranked as P > N > K. Annual N, P and K input to soil through litterfall differed significantly between the two species in the following order: N>K>P. S. robusta was superior in terms of K and P return and T. grandis was superior in terms of N return. The two tree species showed a similar patterns of nutrient release (K > P > N) during decomposition of their leaf litter. Nutrients of N, K and P were the primary limiting nutrients returned to soil through litterfall with important roles in soil fertility and forest productivity.     

Fertility variation in endemic populations of Ehrami black pine (<Emphasis Type="Italic">Pinus nigra</Emphasis> Arnold. subsp. <Emphasis Type="Italic">pallasiana</Emphasis> var. <Emphasis Type="Italic">pyramidata</Emphasis>)

Fertility variation and effective number of parents were estimated in the 100 individuals from each of three plantation populations (P1, P2 and P3) of the endangered Pinus nigra. subsp. pallasiana var. pyramidata established in the Isparta–Golcuk district in southern Turkey in 1990. Potential relations between cone yield and growth characters (height, diameter at breast height, diameter at base and crown diameter) were also investigated. Large differences were found among populations and within populations for cone production and growth characters. Mean cone production was eight (ranging from 6.5 in P2 to 9.1 in P1) for the three populations. The 10 most productive individuals for cones produced 32% of the total cones in P1, 39% in P2 and 34% in P3; 21, 16 and 6 individuals, respectively did not produce any cones in the populations. According to the correlation analyses, the relation between cone yield and growth characters changed for the populations, while height, diameter at breast height and crown diameter were positively significantly correlated (r = 0.182, 0.135 and 0.209; p ≤ 0.05) with cone production for the three populations. Fertility variation was 1.81 in total of three populations, ranging from 1.72 in P3 to 3.45 in P1). Effective number of parents was 142 (55.2 of number of parents censused; 29%, P1; 49.8%, P2; 58.3%, P3).     

Variation in pinewood nematode susceptibility among <Emphasis Type="Italic">Pinus pinaster</Emphasis> Ait. provenances from the Iberian Peninsula and France

Key message

Pinus pinaster Ait. susceptibility to pinewood nematode significantly differed among provenances, and the two Atlantic provenances of the Iberian Peninsula being the most affected. However, significant provenance × environment interaction was found. Provenance susceptibility was related to basal diameter, number of branches and oleoresin flow, and some climatic parameters.

Context

The pinewood nematode Bursaphelenchus xylophilus, native to North America, is an important pest affecting pine forests throughout Eurasia. In Europe, it has been detected in Portugal and Spain and is primarily associated with Pinus pinaster, an important Mediterranean tree species.

Aims

We have investigated the differences in susceptibility among several P. pinaster provenances in the Iberian Peninsula and France, as well as their relationship to certain growth traits and physiological parameters.

Methods

Three independent inoculation tests were performed on 3 to 4-year-old trees, followed by assessment of growth traits and physiological variables, along with time course destructive sampling for nematode quantification.

Results

The results showed significant differences among provenances for almost all growth traits, wilting, and mortality, though a significant provenance × environment interaction was also detected. Two Atlantic provenances, Noroeste-Litoral and Leiria, displayed the largest susceptibility to pinewood nematode. Changes in susceptibility to B. xylophilus between experiments were influenced by temperature and seasonality. Autumn precipitation and mean maximum temperature during summer at the original provenance sites could be related to provenance susceptibility.

Conclusion

Noroeste-Litoral and Leiria were the most disease-affected provenances. This study emphasizes the need for further research on how tree growth stage influences susceptibility and on the possibility of cross-breeding among provenances.

     

Biomass and nutrient allocation to aboveground components in fertilized <Emphasis Type="Italic">Eucalyptus saligna</Emphasis> and <Emphasis Type="Italic">E. urograndis</Emphasis> plantations

The objective of this study was to evaluate biomass allocation and nutrient pools in aboveground biomass components in 18-month-old plantations of Eucalyptus saligna and E. urophylla × E. grandis (i.e. E. urograndis) in Brazil. The plantations were established by pulp companies in a large area comprising three soil types (Acrisols, Vertisols and Leptosols) in the grassland biome in southern Brazil, and an operational regime of planting and maintenance fertilization was used to ensure full availability of nutrients. Vertisols showed the highest availability of soil nutrients, and the P and Ca concentrations in aboveground biomass were also highest in this type of soil. The nutritional status of both species indicates great consumption of nutrients, particularly of P, K and Ca. At this early age, canopy biomass components still made the largest relative contribution, although debarked stem biomass already accounted for 41.5% and 37.4 of total aboveground biomass in E. saligna, and E. urograndis, respectively. Nutrient concentrations in biomass components were similar across species. For all macronutrients, except Ca and Mg, the concentration gradient followed the order wood < bark < branches < leaves. For all micronutrients, except Cu, the concentration gradient followed the order wood < branches ≈ bark < leaves. At the plantation stage studied, i.e. before canopy closure, the importance of the components as nutrient pools followed the order leaves > branches > wood > bark. The branches hold the majority of Ca reserves in biomass and are a very important pool of Mg, K, P and B. The bark makes a small contribution to total biomass, but stores a similar amount of Ca as leaves, being the second major pool after the branches. Comparison of the nutrients supplied by fertilization and the amounts stored in soil and aboveground indicates that the operational dose should be adjusted to each type of soil after further experimental fertilizer trials, as the supply of N and P appears to be too high, particularly for Vertisols. This is leading to the immobilization of P in biomass components that are not of importance in the biological or biochemical nutrient cycles, thus increasing the risk of larger exports of P during biomass removal.     

Effect of hydropriming and acclimation treatments on <Emphasis Type="Italic">Quercus rugosa</Emphasis> acorns and seedlings

To facilitate restoration of the lava field forests surrounding Mexico City, we developed methods to improve the germination and field seedling performance of Quercus rugosa using hydropriming (regulated hydration of seeds in water), and we used special watering regimes to improve seedling acclimation. The size, dry mass, fresh mass and water content of seeds were measured, and curves were generated to evaluate acorn hydration and dehydration. The effects of stratification (5°C), heat shock (50°C) and scarification on germination were tested. All treated seeds and controls were germinated in control chambers at 21°C. One hydropriming cycle (PC) consisted of two hydration days followed by two dehydration days; treatments of 1, 2 and 3 PCs were tested. Seedlings from 1PC to 2PC were acclimated in a shade house under high and low watering regimes (400 and 200 mL week^?1, respectively). In the shade house and field, the effects of hydropriming and watering treatments were evaluated by measuring length, basal diameter, crown cover, number of leaves and branches and leaf area of seedlings. Dry and fresh mass were used to calculate acorn water content. Dehydration and hydration curves displayed hysteresis. Acorns exhibited physiological dormancy, which could be overcome by stratification or by 1 month of storage. 1PC led to increased germination rates and final germination. In both the shade house and field, 1PC showed a positive effect on all seedling growth parameters except branch number. Field survival was not affected. Generally, 1PC favoured efficient seed germination, seedling vigour and homogenous plant production.     

Influence of region of provenance and climate factors on wood anatomical traits of <Emphasis Type="Italic">Pinus nigra</Emphasis> Arn. subsp. <Emphasis Type="Italic">salzmannii</Emphasis>

Region of provenance is defined as an area with uniform ecological conditions where stands with similar phenotypic or genetic features are found. This study assesses the effect of differing climate conditions of eight Spanish regions of provenance of Pinus nigra Arn. subsp. salzmannii on earlywood anatomical traits measured in samples from basal discs from mature trees. Results showed that variation in wood biometry between provenances was high and more pronounced than intrapopulation variation. When comparing P. nigra with other Mediterranean pines, high intertracheid wall strength values are associated with better adaptation of pines to arid conditions. However, the intraspecific variations of this parameter in P. nigra did not follow the same pattern, due to the influence of mechanical support requirements. Trees subject to greater aridity were characterised by short tracheids, apparently resulting from their poorer growth, and high frequency of rays and ray parenchyma cells, which would allow trees to store greater amounts of starch, which is the source of metabolites invested in minimising the limitations imposed by water stress. Severe winter cold spells were strongly associated with high axial resin canal frequency and large radial resin canals, creating a powerful, preformed defence system. Increased tracheid lumen involved an increase in the size of bordered pits, favouring sap flow between tracheids, in addition to an increase in the maximum diameter of cross-field pits, favouring the flow of water and metabolites between the axial and radial systems. The high influence of region of provenance on structural variation in P. nigra shows the importance of provenance in the selection of seed origin for reforestation.