Effects of in situ CO2 enrichment on structural characteristics, photosynthesis, and growth of the Mediterranean seagrass Posidonia oceanica

Seagrass is expected to benefit from increased carbon availability under future ocean acidification. This hypothesis has been little tested by in situ manipulation. To test for ocean acidification effects on seagrass meadows under controlled CO2/pH conditions, we used a Free Ocean Carbon Dioxide Enrichment (FOCE) system which allows for the manipulation of pH as continuous offset from ambient. It was deployed in a Posidonia oceanica meadow at 11 m depth in the Northwestern Mediterranean Sea. It consisted of two benthic enclosures, an experimental and a control unit both 1.7 m**3, and an additional reference plot in the ambient environment (2 m**2) to account for structural artifacts. The meadow was monitored from April to November 2014. The pH of the experimental enclosure was lowered by 0.26 pH units for the second half of the 8-month study. The greatest magnitude of change in P. oceanica leaf biometrics, photosynthesis, and leaf growth accompanied seasonal changes recorded in the environment and values were similar between the two enclosures. Leaf thickness may change in response to lower pH but this requires further testing. Results are congruent with other short-term and natural studies that have investigated the response of P. oceanica over a wide range of pH. They suggest any benefit from ocean acidification, over the next century (at a pH of 7.7 on the total scale), on Posidonia physiology and growth may be minimal and difficult to detect without increased replication or longer experimental duration. The limited stimulation, which did not surpass any enclosure or seasonal effect, casts doubts on speculations that elevated CO2 would confer resistance to thermal stress and increase the buffering capacity of meadows.

Left to right: Gustavo Rubio and Melissa Romigh measuring diameter at breast height (DBH) of mangrove trees at SRS-6, Shark River Slough

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

Drought index from tree-rings in Kongton Mountains, China

The Kongtong Mountain area is a marginal area of the Asian summer monsoon and is sensitive to monsoon dynamics. The sensitivity highlights the need to establishing long-term climate records there and evaluating links with the Asian monsoon. Using "signal-free" methods, we developed a tree-ring chronology based 52 ring-width series from 23 Pinus tabulaeformis and Pinus armandidi trees in the Kongtong Mountain, northern China. Tree growth is highly correlated (0.844) with the Palmer Drought Severity Index (PDSI) from May to July, demonstrating the strength of PDSI in modeling drought conditions in this region. We therefore developed a robust May-July PDSI reconstruction spanning 1615-2009, which explained 71.2% of the instrumental variance for the period 1951-2005. Extremely dry epochs are found in periods of 1723-1727 and 1928-1932, and significant wet conditions are seen from 1696-1700, 1753-1757 and 1963-1969. These persistent dry and wet epochs were also found in northeastern Mongolia, suggesting similar drought regimes between these two regions. The dryness that occurred in the 1920s-1930s was the most severe and was concurrent with a warming period. This warming/drying relationship of the 1920s-1930s may be an analog to the current drying trend in northern China.

Ecophysiology of Adonis distorta, a high-mountain species endemic of the Central Apennines

Morphological, anatomical and physiological plant and leaf traits of A. distorta, an endemic species of the Central Apennines on the Majella Massif, growing at 2,675 m a.s.l, were analyzed. The length of the phenological cycle starts immediately after the snowmelt at the end of May, lasting 128 ± 10 days. The low A. distorta height  (Hmax= 64 ± 4 mm) and total leaf area (TLA= 38 ± 9 cm2) associated to a high leaf mass area (LMA =11.8±0.6 mg cm−2) and a relatively high leaf tissue density (LTD = 124.6±14.3 mg cm−3) seem to be adaptive traits to the stress factors of the environment where it grows. From a physiological point of view, the high A. distorta photosynthetic rates (PN =19.6 ± 2.3 µmol m−2 s−1) and total chlorophyll content (Chla+b = 0.88 ± 0.13 mg g−1) in July are justified by the favorable temperature. PN decreases by 87% in September at the beginning of plant senescence. Photosynthesis and leaf respiration (RD) variations allow A. distorta to maintain a positive carbon balance during the growing season becoming indicative of the efficiency of plant carbon use. The results could be an important tool for conservation programmes of the A. distorta wild populations.

Physico-geochemical and mineral composition of neem tree soils and relation to organic properties

The Neem tree, the oil of which has a long history of pesticide, fertilizer and medicinal use in India, has been studied extensively for its organic compounds. Here we present a physical, mineralogical and geochemical database resulting from the analyses of two Neem soil profiles (epipedons) in India. Neem tree derivatives are used in the manufacture of a variety of products, from anti-bacterial drugs and insecticides to fertilizers and animal feeds. A preliminary geochemical and mineralogical analysis of Neem soils is made to explore the potential for chemical links between Neem tree derivatives and soils. Physical soil characteristics, including colour, texture and clay mineralogy, suggest the two pedons formed under different hydrological regimes, and hence, are products of different leaching environments, one well-drained site, the other poorly drained. Geochemically, the two Neem soils exhibit similarities, with elevated concentrations of Th and rare earth elements. These elements are of interest because of their association with phosphates, especially monazite and apatite, and the potential link to fertilizer derivatives. Higher concentrations of trace elements in the soils may be linked to nutritional derivatives and to cell growth in the Neem tree.

Age and growth of Nassarius reticulatus in the Ria de Aveiro, north-west Portugal

Shell growth of the whelk Nassarius (¼Hinia) reticulatus was studied in the Ria de Aveiro (north-west Portugal) between 1995 and 1998. Temporal analysis of shell height frequency distributions demonstrated that growth occurs during the ¢rst ¢ve years of life, whelks attaining a size of 6.7^7.8 mm in the 1st year, 12.1^14.5 mm in the 2nd year, 18^19.5 mm in the 3rd year, 22.7^23.6 mm in the 4th year and by the 5th year males have achieved an average size of 25 mm whilst females have reached 27 mm. Age estimates from internal microscopic annual growth lines present in the shell lip suggest that large whelks may achieve a longevity of at least 11 years. External annual rings become less discernible as the whelks increase in size and estimates of their age based solely on ring counts can underestimate their age. In males sexual maturation is reached between the 3rd and 4th years whilst in females it is attained between the 4th and 5th years. Imposex was visible in 2 year old females and attained maximum development by the 5th year.

Salicaceae Endophytes: Growth Promotion Potential in Rice (Oryza sativa L.) and Maize (Zea mays L.) and Bio-Control of Plant Pathogen

Thesis (Ph.D.)--University of Washington, 2016-08

Different aspects to consider during kiln drying of Vochysia guatemalensis Donn Sm. Wood (Cebo/Mayo)

Vochysia guatemalensis Donn Sm. wood is currently provided from plantations in several regions of Costa Rica. This wood presents several problems during the drying process such as high variability in the moisture content and high incidence of later defects. The objective of this study was to investigate the causes of this variation and defect developments. It was considered climate condition or precedence, grain pattern, drying schedule, boards position in relation to height and distance from to pith and heartwood presence.  The main factors affecting the moisture variability and drying defects were found to be: high initial moisture content variability in different parts of the tree, climate condition, and improper drying programs. Besides, there are recommendations to consider before starting the drying process. Thus a better wood quality in relation to moisture content variability and the presence of defects can be obtained after drying process.

Hierarchical clustering with multiple-height branch-cut applied to short time-series gene expression data.

Rigid adherence to pre-specified thresholds and static graphical representations can lead to incorrect decisions on merging of clusters. As an alternative to existing automated or semi-automated methods, we developed a visual analytics approach for performing hierarchical clustering analysis of short time-series gene expression data. Dynamic sliders control parameters such as the similarity threshold at which clusters are merged and the level of relative intra-cluster distinctiveness, which can be used to identify "weak-edges" within clusters. An expert user can drill down to further explore the dendrogram and detect nested clusters and outliers. This is done by using the sliders and by pointing and clicking on the representation to cut the branches of the tree in multiple-heights. A prototype of this tool has been developed in collaboration with a small group of biologists for analysing their own datasets. Initial feedback on the tool has been positive.

“He who plants a tree – Plants a hope.” Reforestation possibilities in Tingana, Peru

Tropical forests have decreased drastically especially in the Peruvian Amazon. In Peru deforestation is caused especially by migrant people; building of houses and infrastructure, clearing land for agricultural purposes and illegal logging and mining. Deforestation results in hindering ecosystem vitality, boosting climate change and decreasing livelihood possibilities. As a counterpoint to cutting down trees there is reforestation, which refers to re-establishment of forest cover. Deforestation and reforestation can be analysed in the light of Forest Transition theory. According to it, due to economic growth, the amount forest cover first diminishes but then starts to increase as the economy in general strengthens. Thus, the research framework is set to this theory. In this study the focus is on analysing socioeconomically sustainable reforestation possibilities in the community of Tingana, Peru. It is situated in a municipal conservation area around which deforestation has been heavy. Land cover change is analysed from LandsatTM satellite images covering a 15 year time period, 1995–2010, in the surroundings of the study area. Semi-structured interviews have been done with a sample size of 25 people and shed light on the perspectives on forests, reforestation and economical activities. The synthesis created from the two methods gives information about the possibilities to enforce reforestation in Tingana and the phase of forest transition in the area. The results show that forest cover has decreased around the surroundings of Tingana leaving the conservation area isolated from larger forest areas. Knowing that forest cover has also decreased inside the conservation area due to agricultural expansion it is certain that fragmentation harms biodiversity causing changes in local climate, which can have knock-on effects for farming and local livelihoods. Therefore reforestation is welcomed when it ensures both conservation and financial benefits and when carried out on locals’ terms. Regarding conservation and incomes the best option would be to plant native timber species together with fruit production species to create agroforestry systems. Economically the community should aim towards an economy that relies on ecotourism as it already practiced in the area. Reforestation could increase ecotourism, which then could in turn increase reforestation via revenues. Regarding forest transition it is likely that forest re-establishment will occur if reforestation along with ecotourism is implemented on long time scale.

Influence of Nitrogen and Sink Competition on Shoot Growth of Poplar

Terrestrial and oceanic biomass carbon sinks help reduce anthropogenic CO2 emissions and mitigate the long-term effect of increasing atmospheric CO2. Woody plants have large carbon pools because of their long residence time, however N availability can negatively impact tree responses to elevated CO2. Seasonal cycling of internal N in trees is a component that contributes to fitness especially in N limited environments. It involves resorption from senescing leaves of deciduous trees and storage as vegetative storage proteins (VSP) in perennial organs. Populus is a model organism for tree biology that efficiently recycles N. Bark storage proteins (BSP) are the most abundant VSP that serves as seasonal N reserves. Here I show how poplar growth is influenced by N availability and how growth is influenced by shoot competition for stored N reserves. I also provide data that indicates that auxin mediates BSP catabolism during renewed shoot growth. Understanding the components of N accumulation, remobilization and utilization can provide insights leading to increasing N use efficiency (NUE) of perennial plants.

'Abnormal vertical growth' : A disorder threatening the viability of the Australian macadamia industry

'Abnormal vertical growth' (AVG) was recognised in Australia as a dysfunction of macadamia (Macadamia spp.) in the mid-1990s. Affected trees displayed unusually erect branching, and poor flowering and yield. Since 2002, the commercial significance of AVG, its cause, and strategies to alleviate its affects, has been studied. The cause is still unknown, and AVG remains a serious threat to orchard viability. AVG affects both commercial and urban macadamia. It occurs predominantly in the warmer-drier production regions of Queensland and New South Wales. An estimated 100,000 orchard trees are affected, equating to an annual loss of $ 10.5 M. In orchards, AVG occurs as aggregations of affected trees, affected tree number can increase by 4.5% per year, and yield reduction can exceed 30%. The more upright cultivars 'HAES 344' and '741' are highly susceptible, while the more spreading cultivars 'A4', 'A16' and 'A268' show tolerance. Incidence is higher (p<0.05) in soils of high permeability and good drainage. No soil chemical anomaly has been found. Fine root dry weight of AVG trees (0-15 cm depth) was found lower (p<0.05) than non-AVG. Next generation sequencing has led to the discovery of a new Bacillus sp. and a bipartite Geminivirus, which may have a role in the disease. Trunk cinctures will increase (p<0.05) yield of moderately affected trees. Further research is needed to clarify whether a pathogen is the cause, the role of soil moisture in AVG, and develop a varietal solution.

DESENVOLVIMENTO INICIAL E QUALIDADE DE MUDAS DE Copaifera langsdorffii Desf. SOB DIFERENTES NÍVEIS DE SOMBREAMENTO

As florestas de galeria vêm sendo fragmentadas, levando à perda de sua elevada diversidade, tornando-se imprescindíveis estudos que avaliem o comportamento ecológico de suas espécies arbóreas. O presente estudo teve como objetivo testar a hipótese de que a produção de mudas de Copaifera langsdorffii é influenciada pela luminosidade do ambiente, apresentando maior qualidade e desenvolvimento inicial em níveis intermediários de luz. As plantas foram testadas em pleno sol, 30%, 50%, 70% e 90% de sombreamento, avaliando-se número de folhas, altura e diâmetro aos 60, 90, 120 e 191 dias após a emergência (DAE) e massa seca aérea e radicular e, índice de qualidade de Dickson ao final do experimento (191 DAE). O efeito dos níveis de sombreamento foi analisado por meio de análise de regressão. As plantas apresentaram boa plasticidade de crescimento nos diferentes níveis de luminosidade, mas com melhor desenvolvimento e qualidade (IQD) em 50% de sombreamento, corroborando a hipótese testada. A luminosidade ou sombreamento excessivo devem ser evitados para garantir a produção de mudas mais vigorosas de Copaifera langsdorffii. Assim, recomenda-se a produção de mudas desta espécie sob 50% de sombreamento para favorecer a sua qualidade e possivelmente garantir melhor sobrevivência em campo.

INFLUÊNCIA DA POSIÇÃO SOCIAL NAS RELAÇÕES MORFOMÉTRICAS DE Araucaria angustifolia

The morphometric relations allow describing dimensions of trees without prior knowledge of the age, it help the forest planning and implementation of silvicultural treatments, especially when needs to make sustainable use of forests. For this purpose, the aim of this study was to model and comparising the morphometric relations araucaria trees in social position dominant, codominant and dominated in native forest remnant, located in Lages, SC. A total of 294 trees distributed in dbh classes were intentionally selected inside of forest. In each tree was measured dbh, total height, bole height, crown diameter by eight radius, as well as the classification of social position. Simple and multiple linear regression models were used to describe the relation h/d, the proportion of the crown and formal crown in function of diameter at breast height with simple transformation, quadratic, cubic, inverse and logarithmic form. The analysis of covariance with dummy variables were used to describe the social position and tested the parallelism and slope of regression indicating need or not of the use independent regressions. The results indicated that even with great variability in the shape and size of the crown due to growth and competition process, the morphometric relations of araucaria can be accurately estimated by regression models. The relation h/d, proportion of the crown and formal crown can be described by individual model for social position dominant, codominant and dominant, or alternatively a single model with the use of dummy variables that differentiate trees group dominated for the relation h/d and formal crown. The proportion of crown presented difference in dimensions of the trees, being necessary to use dummy variable for each social stratus or use the individual models.

CARACTERÍSTICAS DENDROMÉTRICAS, QUÍMICAS E DENSIDADE BÁSICA DA MADEIRA DE HÍBRIDOS DE Eucalyptus grandis X Eucalyptus urophylla

O presente trabalho avaliou características dendrométricas, químicas e a densidade básica da madeira de cinco híbridos de Eucalyptus grandis x Eucalyptus urophylla , com 2,25 anos de idade. O experimento foi implantando no espaçamento 3,5 x 2 m, com 35 repetições e parcelas de uma planta. Quatro repetições do experimento foram cortadas avaliando-se o diâmetro a altura do peito (DAP, a 1,3 m do solo), altura total e comercial, biomassa seca de folhas, galhos, madeira e casca, volume com e sem casca e volume de casca. Das árvores abatidas foram retirados discos de 5 cm de espessura no DAP e a 0 (base), 25, 50, 75 e 100% da altura comercial, para determinação da densidade básica e caracterização química da madeira. Os dados foram submetidos à análise de variância e comparação de médias pelo teste de Tukey a 5% de probabilidade. Os clones de Eucalyptus grandis x Eucalyptus urophylla diferiram quanto ao volume e biomassa com destaque para o C5 com valores superiores aos demais clones. A densidade básica da madeira foi maior na base da árvore; nas demais posições de amostragem, os valores de densidade foram semelhantes entre si; dentre os clones, o C5 apresentou densidade básica da madeira superior ao C3 e ao C4, assim como o C2 superou o C3. As características químicas da madeira foram semelhantes entre os clones e, apesar da avaliação ter sido realizada em plantas jovens, os clones demonstraram bom potencial em Jaboticabal - SP.