Relating colour, chemical and physical characteristics of artificially light-aged New Zealand plant fibres

Light ageing of naturally-dyed plant fibres can cause colour change, alteration of molecular bonds within the fibre structure and loss of mechanical integrity. Lighting guidelines seek to protect artefacts by limiting light exposure, for example by estimating the lux hours likely to cause colour change of “one just noticeable fade” (1JNF). However the extent of associated molecular or mechanical damage is rarely simultaneously assessed. This paper reports a pilot study investigating the effects of accelerated light ageing on muka (fibre extracted from the leaves of Phormium tenax), the most common fibre used in Māori textiles. Non-dyed and dyed muka were artificially light-aged and micro-faded to ascertain exposure resulting in 1JNF. Raman microscopy and tensile testing of individual fibres from the same samples were used to explore correlations among fading, molecular change and mechanical properties.Peer Reviewe

Life at the edge: plant responses to extreme alpine environments

Snow is an essential element determining plant composition and performance in alpine environments. Snowbank communities are an ideal model community to identify plant species distribution and plant strategies along environmental gradients. Small-scale changes require plant species-specific adaptations to sustain a population in changing environmental conditions in space and time. Plant strategies (expressed by plant functional traits), without reference to the taxonomy of individual species, can assist to identify vegetation responses to historical and current environmental conditions. In this study, plant traits were quantified along snowmelt gradients in New Zealand and Australian snowbanks, both individually and in a biogeographic context. In summer 2009/2010 the timing of snow release and plant community patterns (by using a transect approach) were measured in six snowbanks in Central Otago, New Zealand, and six snowbanks in the Snowy Mountains, Australia. Selected plant traits (specific leaf area (SLA), leaf dry matter content (LDMC), seed mass, height at maturity, life form) and elevation range (only for New Zealand) were collated for the most abundant vascular plant species at each snowbank site to determine the relationships between their distributions and the snow melt gradient. Plant species trait patterns were analysed for each country, both at the quadrat and species level, and between countries. In New Zealand, measured plant species traits at the quadrat level altered along the snowmelt gradient with seed mass (0.00001 - 0.0028 g), LDMC (120 – 580 mg/g) and height (2 – 290 mm) decreasing and SLA (2 – 34 mm2/g) increasing the later the exposure date. The elevation range of plant species changed across the whole gradient from 1700 to 600m. Species level analysis suggested that plant species at the earliest exposed sites ensure stress resistance through high structural investment (high LDMC), while the latest exposed sites particularly select for strategies associated with reproductive traits (i.e. seed mass). At the species level, at the latest exposed sites shrubs and forbs dominated the earlier exposed sites while graminoids were more frequent at the later exposed areas. In Australia a subset of traits showed strong variations along the snowmelt gradient. At the quadrat level height at maturity (4 – 250 mm) increased the later the exposure date, though the trend was weak, with high variation in the data. Seed mass (0.00001 – 0.04 g) consistently decreased the later the exposure date. At the species level, pant species exhibiting tough, high fibrous leaves (low SLA) were more prominent at the earliest exposed sites (1 – 77 mm2/g). LDMC also displayed an increase (35 -890 mg/g) the later the exposure date within the earliest exposed sites, though the trend was highly variable and weak. Both at earliest and latest exposed sites shrubs dominated the early exposed sites while graminoids and forbs were restricted to later exposed snowbank areas. The comparison between both countries displayed similar trends for height at maturity (decrease) and SLA (increase with later snowmelt). However, LDMC and seed mass showed contrasting trends, with steeper decrease of both seed mass and LDMC in New Zealand. The steeper trait shifts in New Zealand suggest that snowbank habitats are more distinct compared to the apparently more uniform habitats in Australia. In New Zealand, plant species exhibit distinct strategies at the early and late exposed sites to withstand site specific environmental constraints. A trade-off of between resource conservation at the early exposed (long growing season, high LDMC) sites and fast resource acquisition at the late exposed (short growing season, low LDMC) sites is suggested. In contrast, the environmental conditions from early to late exposed sites appear less pronounced in Australia probably because the environmental conditions are more homogenous in the snowbanks habitat along the observed snowmelt gradient. This study provides an understanding of general principles along snowmelt gradients in New Zealand and Australian snowbanks. Further experimental research with a focus on biotic interactions and the distribution of nutrients in the snowbanks is required to complement the findings of this work

Life at the edge: plant responses to extreme alpine environments

Snow is an essential element determining plant composition and performance in alpine environments. Snowbank communities are an ideal model community to identify plant species distribution and plant strategies along environmental gradients. Small-scale changes require plant species-specific adaptations to sustain a population in changing environmental conditions in space and time. Plant strategies (expressed by plant functional traits), without reference to the taxonomy of individual species, can assist to identify vegetation responses to historical and current environmental conditions. In this study, plant traits were quantified along snowmelt gradients in New Zealand and Australian snowbanks, both individually and in a biogeographic context. In summer 2009/2010 the timing of snow release and plant community patterns (by using a transect approach) were measured in six snowbanks in Central Otago, New Zealand, and six snowbanks in the Snowy Mountains, Australia. Selected plant traits (specific leaf area (SLA), leaf dry matter content (LDMC), seed mass, height at maturity, life form) and elevation range (only for New Zealand) were collated for the most abundant vascular plant species at each snowbank site to determine the relationships between their distributions and the snow melt gradient. Plant species trait patterns were analysed for each country, both at the quadrat and species level, and between countries. In New Zealand, measured plant species traits at the quadrat level altered along the snowmelt gradient with seed mass (0.00001 - 0.0028 g), LDMC (120 – 580 mg/g) and height (2 – 290 mm) decreasing and SLA (2 – 34 mm2/g) increasing the later the exposure date. The elevation range of plant species changed across the whole gradient from 1700 to 600m. Species level analysis suggested that plant species at the earliest exposed sites ensure stress resistance through high structural investment (high LDMC), while the latest exposed sites particularly select for strategies associated with reproductive traits (i.e. seed mass). At the species level, at the latest exposed sites shrubs and forbs dominated the earlier exposed sites while graminoids were more frequent at the later exposed areas. In Australia a subset of traits showed strong variations along the snowmelt gradient. At the quadrat level height at maturity (4 – 250 mm) increased the later the exposure date, though the trend was weak, with high variation in the data. Seed mass (0.00001 – 0.04 g) consistently decreased the later the exposure date. At the species level, pant species exhibiting tough, high fibrous leaves (low SLA) were more prominent at the earliest exposed sites (1 – 77 mm2/g). LDMC also displayed an increase (35 -890 mg/g) the later the exposure date within the earliest exposed sites, though the trend was highly variable and weak. Both at earliest and latest exposed sites shrubs dominated the early exposed sites while graminoids and forbs were restricted to later exposed snowbank areas. The comparison between both countries displayed similar trends for height at maturity (decrease) and SLA (increase with later snowmelt). However, LDMC and seed mass showed contrasting trends, with steeper decrease of both seed mass and LDMC in New Zealand. The steeper trait shifts in New Zealand suggest that snowbank habitats are more distinct compared to the apparently more uniform habitats in Australia. In New Zealand, plant species exhibit distinct strategies at the early and late exposed sites to withstand site specific environmental constraints. A trade-off of between resource conservation at the early exposed (long growing season, high LDMC) sites and fast resource acquisition at the late exposed (short growing season, low LDMC) sites is suggested. In contrast, the environmental conditions from early to late exposed sites appear less pronounced in Australia probably because the environmental conditions are more homogenous in the snowbanks habitat along the observed snowmelt gradient. This study provides an understanding of general principles along snowmelt gradients in New Zealand and Australian snowbanks. Further experimental research with a focus on biotic interactions and the distribution of nutrients in the snowbanks is required to complement the findings of this work

Ecological responses to 52 years of experimental snow manipulation in high-alpine cushionfield, Old Man Range, south-central New Zealand

Periodic monitoring over 52 years have revealed temporal changes in the vegetation and floristic patterns associated with what has been acclaimed to be the world's oldest known experimental snow fence, which is located on an exposed high-alpine cushionfield on the Old Man Range in south-central New Zealand. The induced pattern of intermittent snow-lie has been increased by the fence from the normal ∼140 days to more than 200 days (and up to 140 cm deep), estimated from subsurface soil temperatures, together with periodic observations and measurements of snow depth. Some but not all species associated with natural snowbanks on the range have established in areas of induced snow accumulation. The timing of species establishment was not obviously related to relevant features of the local snowbank species or their distribution on the range, but the abundance of various plant species and their functional traits across zones of snowmelt point to competition and plant productivity being associated with the deepest snow in the lee of the fence. In addition, three of the several measured physical and chemical soil factors (Mg, available PO43-, and C:N) have differentiated significantly in relation to the vegetation and snow-lie pattern at year 52, although these seem not to be relevant on the basis of the pattern of the same factors in two nearby natural snowbanks on the range

Tundra Trait Team : A database of plant traits spanning the tundra biome

Motivation The Tundra Trait Team (TTT) database includes field-based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade-offs, trait-environment relationships and environmental filtering, and trait variation across spatial scales, to validate satellite data, and to inform Earth system model parameters. Main types of variable contained Spatial location and grain The database contains 91,970 measurements of 18 plant traits. The most frequently measured traits (> 1,000 observations each) include plant height, leaf area, specific leaf area, leaf fresh and dry mass, leaf dry matter content, leaf nitrogen, carbon and phosphorus content, leaf C:N and N:P, seed mass, and stem specific density. Measurements were collected in tundra habitats in both the Northern and Southern Hemispheres, including Arctic sites in Alaska, Canada, Greenland, Fennoscandia and Siberia, alpine sites in the European Alps, Colorado Rockies, Caucasus, Ural Mountains, Pyrenees, Australian Alps, and Central Otago Mountains (New Zealand), and sub-Antarctic Marion Island. More than 99% of observations are georeferenced. Time period and grain Major taxa and level of measurement All data were collected between 1964 and 2018. A small number of sites have repeated trait measurements at two or more time periods. Trait measurements were made on 978 terrestrial vascular plant species growing in tundra habitats. Most observations are on individuals (86%), while the remainder represent plot or site means or maximums per species. Software format csv file and GitHub repository with data cleaning scripts in R; contribution to TRY plant trait database (www.try-db.org) to be included in the next version release.Peer reviewe

Sequential high-dose cytarabine and mitoxantrone (S-HAM) versus standard double induction in acute myeloid leukemia—a phase 3 study

Dose-dense induction with the S-HAM regimen was compared to standard double induction therapy in adult patients with newly diagnosed acute myeloid leukemia. Patients were centrally randomized (1:1) between S-HAM (2nd chemotherapy cycle starting on day 8 - dose-dense) and double induction with TAD-HAM or HAM(-HAM) (2nd cycle starting on day 21 - standard). 387 evaluable patients were randomly assigned to S-HAM (N - 203) and to standard double induction (N - 184). The primary endpoint overall response rate (ORR) consisting of complete remission (CR) and incomplete remission (CRi) was not significantly different (P = 0.202) between S-HAM (77%) and double induction (72%). The median overall survival was 35 months after S-HAM and 25 months after double induction (P = 0.323). Duration of critical leukopenia was significantly reduced after S-HAM (median 29 days) versus double induction (median 44 days)-P < 0.001. This translated into a significantly shortened duration of hospitalization after S-HAM (median 37 days) as compared to standard induction (median 49 days)-P < 0.001. In conclusion, dose-dense induction therapy with the S-HAM regimen shows favorable trends but no significant differences in ORR and OS compared to standard double induction. S-HAM significantly shortens critical leukopenia and the duration of hospitalization by 2 weeks

Tundra Trait Team:a database of plant traits spanning the tundra biome

Abstract Motivation: The Tundra Trait Team (TTT) database includes field‐based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade‐offs, trait–environment relationships and environmental filtering, and trait variation across spatial scales, to validate satellite data, and to inform Earth system model parameters. Main types of variable contained: The database contains 91,970 measurements of 18 plant traits. The most frequently measured traits (&gt; 1,000 observations each) include plant height, leaf area, specific leaf area, leaf fresh and dry mass, leaf dry matter content, leaf nitrogen, carbon and phosphorus content, leaf C:N and N:P, seed mass, and stem specific density. Spatial location and grain: Measurements were collected in tundra habitats in both the Northern and Southern Hemispheres, including Arctic sites in Alaska, Canada, Greenland, Fennoscandia and Siberia, alpine sites in the European Alps, Colorado Rockies, Caucasus, Ural Mountains, Pyrenees, Australian Alps, and Central Otago Mountains (New Zealand), and sub‐Antarctic Marion Island. More than 99% of observations are georeferenced. Time period and grain: All data were collected between 1964 and 2018. A small number of sites have repeated trait measurements at two or more time periods. Major taxa and level of measurement: Trait measurements were made on 978 terrestrial vascular plant species growing in tundra habitats. Most observations are on individuals (86%), while the remainder represent plot or site means or maximums per species. Software format: csv file and GitHub repository with data cleaning scripts in R; contribution to TRY plant trait database (www.try-db.org) to be included in the next version release