Carbon dioxide enrichment affected flower numbers transiently and increased successful post-pollination development stably but without altering final acorn production in mature pedunculate oak (Quercus robur L.)

Acorn production in oak(Quercus spp.)shows considerable inter-annual variation,known as masting,which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commercial tree planting each year.Anthropogenic emissions of greenhouse gases have been very widely reported to influence plant growth and seed or fruit size and quantity via the‘fertilisation effect’that leads to enhanced photosynthesis.To examine if acorn production in mature woodland communities will be affected by further increase in CO_(2),the contents of litter traps from a Free Air Carbon Enrichment(FACE)experiment in deciduous woodland in central England were analysed for numbers of flowers and acorns of pedunculate oak(Quercus robur L.)at different stages of development and their predation levels under ambient and elevated CO_(2) concentrations.Inter-annual variation in acorn numbers was considerable and cyclical between 2015 and 2021,with the greatest numbers of mature acorns in 2015,2017 and 2020 but almost none in 2018.The numbers of flowers,enlarged cups,immature acorns,empty acorn cups,and galls in the litter traps also varied amongst years;comparatively high numbers of enlarged cups were recorded in 2018,suggesting Q.robur at this site is a fruit maturation masting species(i.e.,the extent of abortion of pollinated flowers during acorn development affects mature acorn numbers greatly).Raising the atmospheric CO_(2) concentration by 150μL L^(−1),from early 2017,increased the numbers of immature acorns,and all acorn evidence(empty cups+immature acorns+mature acorns)detected in the litter traps compared to ambient controls by 2021,but did not consistently affect the numbers of flowers,enlarged cups,empty cups,or mature acorns.The number of flowers in the elevated CO_(2) plots’litter traps was greater in 2018 than 2017,one year after CO_(2) enrichment began,whereas numbers declined in ambient plots.Enrichment with CO_(2) also increased the number of oak knopper galls(Andricus quercuscalicis Burgsdorf).We conclude that elevated CO_(2) increased the occurrence of acorns developing from flowers,but the putative benefit to mature acorn numbers may have been hidden by excessive pre-and/or post-dispersal predation.There was no evidence that elevated CO_(2) altered masting behaviour.

Development of cork oak (Quercus suber L.) seedlings in response to tree shelters and mulching in northwestern Tunisia

The need for reforestation in cork oak （Quercus suber L.） areas is challenged by difficulties. Principal among these is herbivory of young plants, vegetative competition, and slow growth rates of cork oak seedlings. We evaluated the early development of cork oak seedlings treated using tree shelters and mulching in northwestern Tunisia. We tested three tree shelter treatments （non-vented, vented, and control） to shield seedlings from animal damage and five mulch types to control competing vegetation （Italian Stone Pine, Lentisk, combination of Italian Stone Pine and Lentisk （organic mulches）, gravel （inorganic mulch） and no mulch）. At the end of the two-year experiment, sheltered seedlings were 89-99% taller than unshelteredseedlings and had higher numbers and lengths of shoot growth flushes. In contrast, both stem diameter growth and dry weight biomass （from samples extracted after two years） were significantly reduced inside tree shelters. Root-to-shoot ratio was not significantly different in sheltered vs. unsheltered seedlings, suggesting that tree shelters do not adversely affect this parameter. Mulching alone did not favour growth, but could be beneficial when combined with tree shelters. The combination of vented tree shelters and gravel mulch was the most effective treatment for promoting diameter, height and stem volume growth.

Effect of Amino Acids on Secondary Somatic Embryogenesis of Moroccan Cork Oak (<i>Quercus suber</i>L.) Tree

In the present study, we tested the effect of amino acids on secondary somatic embryogenesis of Moroccan cork oak (Quercus suber L.). Secondary mature and immature somatic embryos were obtained from primary somatic embryos cultured in N30K medium supplemented with nineteen amino acids. Stimulation of embryogenesis was dependent on the type and concentration of amino acid in the medium. Thus, L-glutamine and L-asparagine at 3.42 mM have been proved to be the most favorable for the formation of functional somatic embryos and the induction of secondary somatic embryos.

Effect of moisture on physical parameters of timber from Turkey oak (Quercus cerris L.) coppice in Central Italy

This study aims to investigate wood density at different levels of moisture, basic density and shrinkage of timber from Turkey oak （Quercus cerris L.） coppice forests growing in Central Italy. We also studied the variability in density in the trees within and among sites. Density shows no significant statistical differences in the tested population. A higher variability in the shrinkage than in the density was found. Wood moisture is referred to as dry mass and fresh mass, which is related to many performance characteristics of wood, i.e., energy production. Trends in moisture and water content were studied because these physical parameters play an important role in the specific area of firewood which requires an accurate estimation of mass, volume and energy content. This work is a contribution to improve xylo-energy estimates of small and medium forestry issues.

Canopy Net Photosynthesis Rate of a Mongolian Oak (<i>Quercus mongolica</i>) Forest Estimated by Field Experimental Data

The canopy net photosynthesis rate of Mongolian oak (Quercus mongolica) tree species that are dominant in East Asia and Korea is estimated with empirical models derived from field experimental data obtained from the Nam-San site in Seoul, Korea for the growing period from early May to late October in 2010. The empirical models include the attenuation function of photosynthetic photon flux density (PPFD) (r2 = 0.98-0.99, p r2 = 0.99, p < 0.001) derived from the measured data at several levels within the canopy. The incident PPFD at each level within canopy significantly varies diurnally and seasonally due to the seasonal variation of the total plant area index (TPAI = leaf area index + wood silhouette area index) and the light shielding effect of light path-length through the canopy in association with the variation of solar elevation angle. Consequently, a remarkable seasonal variation of the total canopy net photosynthesis rate of Q. mongolica forest stand is found for its growing period. The PPFD exceeding 1000 μmol m-2·s-1 is found to cause the decrease of net photosynthesis rate due to the thermal stress in the early (May) and late (September) growing period. During the whole growing season, the estimated total canopy net photosynthesis rate is found to be about 3.3 kg CO2 m-2.

Evaluation of Phenotypic Diversity by Use of Variable Analysis Multi of Various Populations of Oak Cork (<i>Quercus suber</i>L.) in Tunisia

Populations of oak cork (Quercus suber L.) originated from different areas in Tunisia were analysed based on morphological characters to assess the overall degree of phenotypic variability, to detect similarities between the genotypes and to evaluate significant forest features. One-way ANOVA analysis shows a significant difference between oak cork populations and demonstrates that parameters measured on leaves show an important degree of variability and permit to discriminate oak cork individuals. Vegetative variables are leaf length, leaf width, petioles length, number of leaf veins, petioles width, spines number, leaf area, length nipples, diameter nipples, weight nipples, and height trees. Diameter trees were scored and subjected to multivariate analysis. Results showed a considerable diversity among local germoplasme of oak cork. Principal component analysis (PCA) revealed that the characters related to the length and width of the sheets and the nipples accounted for a large proportion of the observed variability. Cluster analysis showed a typically continuous phenotypic diversity among oak cork accessions, and little asso-ciations between accessions from same geographic origin. Also, some heterogeneity within accessions that received the same denomination was evidenced. The variability observed between different populations is attached to phenotypic characters which depend primarily on two factors, gene and environment.

Macronutrients Effect on Secondary Somatic Embryogenesis of Moroccan Cork Oak (<i>Quercus suber</i>L.)

To define the preliminary embryogenesis culture conditions of Moroccan Cork Oak (Quercus suber L.) in secondary propagation systems, secondary embryos formation from primary embryos were analyzed using seven macronutrient medias: (Chalupa) (BTM), Murashige and Skoog (MS), Schenk and Hildebrant (SH), Schenk and Hildebrant with half content macronutrients (SH ?), full Gamborg (G), Margara (N30K) and Woody Plant Media(WPM). Mature primary embryos at cotyledonal stage of 8 - 10 mm, were placed in each culture medium, and supplemented with 30 g/l of glucose and 7 g/l of agar without PGR. The experimental design consisted of a Petri dish containing three embryos explants. Each one of the seven treatments was composed of ten Petri dishes. Mean number of secondary somatic embryos, clusters and new embryogenic formation on clusters were recorded after 8 weeks, and evaluated by statistical analysis. There were no significant differences (p ≤ 0.05) in clusters and new embryos on clusters formation among evaluated media;but mean number of secondary embryos was significantly higher in N30K (4.37 ± 0.48) compared with control media (1.37 ± 0.15). The morphology of secondary embryos grown in the N30K medium exclusively showed the presence of three embryogenic stages: early cotyledonal with translucide aspect, white opaque, or green, and mature embryos. These results indicate that the medium do influence the morphogenic characteristics of produced embryos. Our finding revealed that secondary somatic embryos produced in N30K medium presented better morphogenic potential, with different stages of embryogenic formation.

Callogenesis of Cork Oak(Quercus suber L.)through In Vitro Culture of Nodes and Internodes

The present study is about in vitro culture of cork oak, through callogenesis from nodes and internodes, withdrawn from seedlings of three months. These latter were obtained after acorns germination on peat. Nodes showed a high capacity for callogenesis and the best rate was obtained on a medium containing Woody Plant Medium (WPM) macronutrients, Murashige and Skoog (MS) micronutrients and vitamins, 4.5 μM of 6-Benzylaminopurine (BAP), 7 μM of 2-naphthalineacetic acid (NAA) and 30 g/L of Sucrose. Calluses are transplanted onto the same mineral solution, with or without growth regulators, and in the 3rd transplanting;small white embryos appear on the surface of calluses.

Comparison of Major Nutrient Release Patterns of Quercus liaotungensis Leaf Litter Decomposition in Different Climatic Zones

Leaf litter decomposition of liaotong oak (Quercus liaotungensis Koize) under temperate, subtropical and tropical forests was examined using a litter bag technique. Decomposition rates and release dynamics of nutrients Ca, Cu, Fe, K, Mg, Mn and P were observed separately at all three sites for I to 2 a periods. The leaf litter mass loss of liaotong oak was simulated with Olson's exponential model. Significant differences of leaf litter mass loss were found in forests of all three climate zones. Litter decomposition was accelerated with the increase of both annual mean precipitation and temperature. Our results agreed with other studies demonstrating that litter decomposition processes were greatly affected not only by soil organisms (including soil fauna and microorganisms), but also by chemical factors. These chemical factors were important for controlling the release of nutrients, especially elements of Fe and Mn. We also found that Fe and Mn content increased in semi-decayed leaf litter as litter mass decreased. This result was presumably due to chelating process which accumulated soil Fe and Mn ions into the decomposing litter. In conclusion, our study allowed us to determine the classification of the characteristics of different nutrient release patterns.

Influence of Amino Acids on the Secondary Somatic Embryogenesis Proliferation Process of Moroccan Cork Oak (<i>Quercus suber</i>L.)

The present study aims to explore the regeneration potential of Moroccan cork oak through the secondary somatic embryogenesis process. Particularly, we focus on the analysis of amino acids influence on the quantity and quality of the regenerated secondary embryos. The amino acids tested are: Glutamine, asparagine, arginine, tryptophane, methionine, casein hydrolysate and urea. Each amino acid is added in the Margara (N30K) medium at different concentrations ranged between 10 and 500 mg/l. The results are collected after 2 months of culture. First analysis shows that the glutamine and the casein hydrolysate gives a maximum number of somatic embryos, clusters and pre-embryos newly formed on the clusters. By comparison to the control medium, the increase of the secondary embryos number directly formed exceed 36% in the case of casein hydrolysate and 35% of in the case of glutamine both at the concentration of 30 mg/l. However, the test of the combination of these amino acids did not have any significant results. In terms of quality, the influence of amino acids on the morphology of secondary embryos was analyzed.

采用改良CTAB法提取柞树(Quercus L.)基因组DNA

为了获得质量较高的柞树基因组DNA，采用经过改良的十六烷基三乙基溴化铵（CTAB）提取法对几种常见柞树植物进行基因组DNA的提取，所得到的DNA样品经紫外分光光度计和琼脂糖凝胶电泳检测，纯度较高，D260nm／D280nm为1．75～1．80，应用于SSR和RAPD标记分析时，可以获得较好的扩增片段。

埋藏和环境因子对辽东栎(Quercus liaotun-gensis Koidz)种子更新的影响(英文)

辽东栎萌生丛零散地分布在北京山区 ,虽然其种子量很大 ,但自然状况下的实生苗非常稀少。鼠类搬运并吃掉大量散落在地表的辽东栎种子 ,但鼠类是否影响辽东栎的自然更新尚不清楚。本研究主要在于了解 :( 1 )将种子埋入土层内后对辽东栎种子出苗率的影响 ;( 2 )环境因子 (如坡向、地表植被等 )对辽东栎种子出苗率的影响。 1 996年 9月 2 4日 ,选取 5块样地 ( Site) ,在每块样地各设置 1条样线 ( Transect) ,每条样线上设置若干样点 ( Plot) ,样点间隔 1 0 m,用于种子埋藏实验。在每个样点设置 6条平行线 ( Parallel transect) ,间隔 1 0 cm,各埋入 1 0粒种子 ,种子间隔 2 cm;第 1、2、3、4、5、6条线的埋藏深度分别为 0、2、4、6、8、1 0 cm。分别于 1 997年 6月 1 5日和 1 0月 4日调查出苗情况。研究结果表明 ,夏季和秋季辽东栎种子出苗率均与埋藏深度呈正相关。埋藏通过改善湿度和减少鼠类等动物的取食而增加了出苗率 ,其贡献分别占 1 8%和 1 2 %。但鼠类对埋入土层内种子的取食率依然很高 ( 87% )。辽东栎种子在阴坡和阳坡的最终出苗率都很高 ,但阳坡出苗要早于阴坡。夏季辽东栎种子出苗率均与地表植被覆盖度呈负相关。地表植被可能是通过与辽东栎种子竞争水分和养分而降低辽东栎种子出苗率的。辽东栎?

Response of photosynthesis,growth,and acorn mass of pedunculate oak to diff erent levels of nitrogen in wet and dry growing seasons

The objective was to examine the effects of optimal leaf nitrogen levels>2.0%and suboptimal levels<2.0%,nitrogen nutrition on net photo synthetic rate,stem diameter increment,height growth increment and acorn mass of pedunculate oak during 2010 in the absence of drought stress and during 2011 under the impact of moderate drought stress.According to the results,moderate drought stress significantly reduced net photo synthetic rate,stem diameter increment and height growth increment,while acorn mass was not affected.Suboptimal nitrogen nutrition significantly reduced the net photo synthetic rate and stem diameter increment only in the wet year,acorn mass in both wet and dry years,while height growth increment was not significantly reduced by suboptimal nitrogen nutrition in either year.The results indicate that optimal nitrogen levels can stimulate photo synthetic rate and stem diameter increment of pedunculate oak only in the absence of moderate drought stress.Moreover,the results show that moderate drought stress is a more dominant stressor for photosynthesis and growth of pedunculate oak than suboptimal nitrogen nutrition,while for acorn development,it is the more dominant stressor.

Research advances in allelopathy of Quercus L.

The term allelopathy refers to biochemical interaction between all types of plants including microorganisms through production of chemical compounds that escape into the environment and exist widely in Quercus L. The development of investigations into types of allelochemicals, their compounding and spreading pathways, as well as expression of allelopathy in Quercus L. are reviewed in this paper： We have closely and systematically emphasized the functional mechanisms of allelopathy in forest plants for our next research project on allelopathy in Quercus L.

Ecological variables influencing the diversity and distribution of macrolichens colonizing Quercus leucotrichophora in Uttarakhand forest

Ecological variables play a significant role in determining the diversity and distribution of any living organism on earth. Lichens are not exceptional and are quite sensitive in comparison to other organisms; hence the present study focuses on the impact of ecological variables on the diversity and distribution of epiphytic macrolichens colonizing Quercus leucotrichophora across eight different sites(50 m × 50 m) in Thal Ke Dhar forest, Kumaun Himalaya, Uttarakhand, India. For sampling of macrolichens, 200 trees(25 trees from each site) of Q.leucotrichophora were selected from each site and five quadrats of 5 cm × 10 cm(1000 quadrats in totality) were drawn at the tree trunk. From all the sampled trees, a total of 54 species of epiphytic macrolichens belonging to 18 genera and five families were recorded. Various ecological variables, namely altitude, aspect, slope, diameter at breast height(DBH), and lopping percent(partial cutting of the twigs as disturbance), were also analyzed to investigate their influence on macrolichen species composition and distribution pattern in the study area. For the determination of relationships between these variables, statistical analysis, namely Pearson's Correlation Coefficient, Polynomial regression analysis and Principal Component Analysis(PCA)were performed. Out of all variables, lopping was significantly correlated to species richness of epiphytic macrolichens(0.712~*, p<0.05) and it was confirmed by Pearson's Correlation Coefficient.Despite of having high anthropogenic pressure or impact through lopping, the maximum number of macrolichen species was recorded at elevation 2267 meter above sea level(m asl). The present study revealed that besides other ecological variables,lopping practices can act as a key parameter incontrolling the diversity and distribution not only of epiphytic macrolichens but also of other life forms such as bryophytes, pteridophytes, insects, birds etc.and can be either negatively or positively correlated.

Linking morphological and ecophysiological leaf traits to canopy dieback in Persian oak trees from central Zagros

Intraspecific variability in morphological and ecophysiological leaf traits might be theorized to be present in declining populations,since they seem to be exposed to stress and plasticity could be advantageous.Here we focused on declining Persian oaks(Quercus brantii Lindl.var.persica(Jaub and Spach)Zohary)in the Zagros Mountains of western Iran,representing the most important tree species of this region.We selected trees with contrasting crown dieback,from healthy to severely defoliated,to investigate the relationships between canopy dieback and leaf morphology,water content and pigments.We also measured esterase and peroxidase,as enzymatic antioxidants and indicators of contrasting genotypes.Trees showing moderate to severe defoliation showed higher leaf mass area(LMA),reduced relative water content(RWC),and lower stomatal density(SD).Increasing LMA indicates a more sclerophyllic structure,according to drier conditions.We did not find significant differences in leaf pigments(chlorophyll a and b,and carotenoids)among crown dieback classes,suggesting that Persian oak trees are able to maintain accurate photochemical efficiency,while reduced RWC and SD suggest hydraulic limitations.Our results do not provide a consistent pattern as regards enzymatic antioxidant defense in Persian oak.Morphological leaf traits would be important drivers of future adaptive evolution in Persian oak,leading to smaller and thicker leaves,which have fitness benefits in dry environments.Nonetheless,drought responses may be critically affecting carbon uptake,as photosynthetic compounds are less effectively used in leaves with higher sclerophylly.

Application of Theoretical Growth Functions for Mongolian Oak(Qurcus Mongolica)

Four alternative functions are used for lilting tree height and diameter growth models for mongolian oak(Quercus mongolica Fisch et Turcz)The data set includes 1250 random trees and 755 dominant trees coming from 510lemporary plots The resultsshow that the Richads function is the best model for predicting height diameter at breast height(DBH) and dominant height from age The average growth curveof domnant height is used as a guide curve for the construction of a site index table which is partially validated using an independent data set The Mischerlic function is the bestmodel for estimating height and dominam height from DBH

Rehabilitating Degraded Hardwood Stands on a Bottomland Terrace Site with Overstory Removal and Oak Enrichment Planting: 14-Year Results

Exploitative harvesting can lower stand quality in the short term and diminish forest productivity over the long term. In 2003, a rehabilitation experiment was installed in a southern hardwood stand on a bottomland terrace site, degraded by periodic exploitative cutting, to test the effectiveness of overstory removal and oak enrichment planting for improving stand quality and composition. Overstory removal treatments included clearcutting, stand improvement partial cutting, and an uncut control. Overstory treatment units were either planted with Nuttall oak (Quercus texana) seedlings or not planted. We revisited this study in 2017 to assess the outcome of oak enrichment planting across levels of overstory removal. Results in year 14 indicated poor survival of planted oaks under all overstory removal treatments (14% - 24%) and minimal height growth (0.3 m in 13 years) in areas treated with partial cutting and in uncut areas. Growth performance of planted oaks was significantly enhanced by clearcutting (p < 0.01). However, the overwhelming response of natural oak regeneration initiated by clearcutting trumped the contribution from enrichment planting on this low quality bottomland terrace site. Enrichment planting of Nuttall oak did not increase oak regeneration success in our study. The ineffectiveness of enrichment planting in this study was likely related to the shady understory of partially cut stands and intense competition in clearcuts. Additional treatments, such as pre-planting site preparation and post-planting release may be necessary for enhancing and maintaining competitiveness of planted red oak seedlings on similar sites.

有效微生物群对红栎容器苗生长及其基质理化性质的影响

探究了不同浓度有效微生物群(EM)和不同基质对红栎容器苗生长及土壤理化性质的影响,以筛选出最合理的施肥方案。以红栎1年生容器苗为实验材料,分别在黄心土(S)、菇渣与黄心土(M)(体积比1∶4)的混合基质内施用不同浓度的EM,另设珍珠岩与黄心土(P)(体积比1∶4)的混合基质内不施EM以及黄心土施复合肥的处理,分别在6-10月份的每月10日测定其苗高、地径、生物量,于10月10日后测定土壤的理化性状等指标。结果表明:各处理均对红栎1年生容器苗的生长有促进作用,以菇渣和黄心土混合,EM稀释倍数为50时(处理M_(4))生长量达到最大,到10月份时,苗高、地径、总鲜重、总干重分别达到38.86 cm、5.77 mm、54.08 g、28.88 g,分别较S_(1)提高了48.66%、40.39%、81.35%、71.80%;所有施EM的处理中,除S_(2)、S_(3)、S_(4)的速效磷、S_(2)、M_(3)的pH值外,其余指标均与S_(1)有显著差异。黄心土(S处理)和菇渣混合基质(M处理)均是在施用EM浓度最高时理化性状整体效果最好,且M_(4)效果优于S_(4),两者的效果也优于其他任何不施EM的效果。本试验以菇渣与黄心土混合,EM稀释倍数为50(M_(4))最有利于红栎幼苗生长发育,为红栎一年生容器苗最佳施肥处理。

Status and distribution pattern of coarse woody debris along an altitudinal gradient in Askot Wildlife Sanctuary, Uttarakhand, West Himalaya

A rapid assessment on the status and distribution patterns of coarse woody debris （CWD） was conducted by laying five curvilinear transects （transects A, B, C, D and E; major trails）, along an altitudinal gradient starting from 900 to 2 600 m, in three major watersheds （Charigad, Dogarhigad and upper Gosigad） of Goriganga catchment in Askot Wildlife Sanctuary, India. At every 100 m rise in altitude a hectare plot （100 m x 100 m） was selected. Results showed that the percentage contribution by different succession phases was in the decreasing order： phase I 〉 phase II 〉 phase IV 〉 phase III for snags, and phase III〉 phase II 〉 phase IV 〉 phase I for logs. Snag density in chir pine forest was high in transect A （11 snags＇ha^-1） at 1 500 m, and the value in rianj oak forest was high in transect B （10 snags.ha-l） at 2 300 m. The total available mass of snags and logs in chit pine forest was 13.9 t, of which snags mass accounted for 41% of the total mass and logs mass for 59%. While the total value was 5.6 t in rianj oak forest, of which snags and logs accounted for 60% and 40% of the total mass, respectively. Moreover, the presence of CWD in the study area if not harvested, would provide a great opportunity to the orchids in future to flourish by providing protection. The high densities of snags and logs in chir pine forest at mid-altitudinal zone led to less species richness and lower density of ground flora as the zone receives more light, accompanying with lower soil moisture, and thus only the dominant species occupy the habitat.