Fucai Xia

Tilia mandshurica is a multi-purpose tree species with high values for timber production, landscape ornamentation, and nectar yield. Growth traits serve as core evaluation indices for its genetic improvement, and clarifying the maternity–progeny genetic relationship is essential for efficient selective breeding. In this study, 66 maternal clones and their corresponding open-pollinated progeny families derived from the same plus trees were used as experimental materials. Six key growth traits, including tree height, basal diameter, clear bole height, branch angle, crown width, and stem straightness, were systematically measured and analyzed. Extremely significant variances in all investigated growth traits were observed among both maternal clones and progeny families. For maternal clones, the phenotypic coefficient of variation, genotypic coefficient of variation, and repeatability ranged from 37.3% to 77.2%, 1.0% to 29.1%, and 0.4286 to 0.6587, respectively. For progeny families, the phenotypic coefficient of variation and genotypic coefficient of variation varied from 35.4% to 66.9% and 0.7% to 26.7%, with heritability ranging from 0.3671 to 0.6255. Significant phenotypic and genetic correlations for growth traits were detected between maternal clones and progeny families, excluding stem straightness. Integrated principal component analysis and multi-trait comprehensive evaluation screened eight elite maternal clones (LJ03, LJ19, LJ21, LJ32, LJ40, LJ47, LJ52, LJ63) and ten elite progeny families (LJ03, LJ09, LJ21, LJ27, LJ32, LJ40, LJ46, LJ47, LJ52, LJ63). Among these materials, seven germplasms (LJ03, LJ21, LJ32, LJ40, LJ47, LJ52, LJ63) exhibited excellent performance in both clonal and family populations. The elite clones yielded genetic gains of 4.4–26.2% and realistic gains of 10.3–42.4%, while the elite families presented genetic gains of 1.5–21.2% and realistic gains of 3.1–33.8%. This study clarifies the genetic variation and maternity –progeny genetic linkage of growth traits in T. mandshurica, provides excellent elite germplasm resources for genetic improvement, and offers a theoretical and practical basis for the future construction of high-quality seed orchards of this species.

Cornus officinalis Sieb. et Zucc. is a medicinal and ornamental woody plant whose distribution and production may be increasingly affected by climate change. This study assessed its climatic suitability under paleoclimatic, current, and future conditions to provide a climatic basis for cultivation planning, introduction, and germplasm conservation. An optimized MaxEnt model was developed using 381 spatially filtered occurrence records and five environmental predictors. Model complexity was tuned using spatial block cross-validation, and future projections for 2081–2100 were generated from an ensemble of ACCESS-CM2, BCC-CSM2-MR, and CMCC-ESM2 under four Shared Socioeconomic Pathway scenarios. Cold-quarter temperature, warm-season precipitation, mean diurnal temperature range, precipitation seasonality, and slope jointly shaped the predicted distribution. Under the current climate, climatically suitable areas were concentrated mainly in East Asia, particularly central and eastern China, with additional suitable climatic regions in eastern North America and parts of Europe. Suitable area was smallest during the Last Interglacial, expanded during the Last Glacial Maximum, and approached its current extent during the Mid-Holocene. The current suitable area was estimated at 277.247 × 10⁴ km² and was projected to decrease to 243.689, 206.615, 201.393, and 206.168 × 10⁴ km² under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, respectively. Existing suitable areas contracted in central China, the southern United States, and southern Japan, whereas climatic suitability expanded northward in parts of China, North America, Japan, and Europe. Suitable-area gains did not offset losses under any scenario, and retention of current suitable areas declined from 52.88% under SSP1-2.6 to 19.74% under SSP5-8.5. Most newly suitable areas were supported by at least two of the three climate models, although greater inter-model variation occurred near some range margins. These findings indicate substantial future redistribution of climatic suitability and identify climatically stable and newly suitable regions that may inform climate-resilient cultivation planning and conservation of C. officinalis.

The Arctic tundra is a relatively young and new type of biome and is especially sensitive to the impacts of global warming. However, little is known about how the Arctic flora was shaped over time. Here we investigate the origin and evolutionary dynamics of the Arctic flora by sampling 32 angiosperm clades that together encompass 3626 species. We show that dispersal into the Arctic and in situ diversification within the Arctic have similar trends through time, initiating at approximately 10–9 Ma, increasing sharply around 2.6 Ma, and peaking around 1.0–0.7 Ma. Additionally, we discover the existence of a long-term dispersal corridor between the Arctic and western North America. Our results suggest that the initiation and diversification of the Arctic flora might have been jointly driven by progressive landscape and climate changes and sea-level fluctuations since the early Late Miocene. These findings have important conservation implications given rapidly changing climate conditions in the Arctic.

Instytut Dendrologii PAN w Kórniku - Institute of Dendrology PAS (Kórnik, Poland)

研究林下草本植物不同生长期生物量分配及各组分相关生长关系对于揭示其生活史对策和生物量分配规律具有重要意义. 利用2015年4月20日-8月30日11次生物量调查数据分析吉林蛟河地区针阔混交林下不同生长期蚊子草（Filipendula palmata）生物量及其分配、地上和地下生物量相关生长关系，并选取5种模型形式构建株高与地上、地下和整株生物量的拟合方程，根据拟合优度（R2和SEE）筛选最优模型并进一步对其进行检验. 结果表明：根冠比R/S在生长初期达到最大值（2.73），并随生长期增加逐渐降低，从5月20日后到生长末期趋于稳定（约为0.6）. 整个生长期内，蚊子草地上和地下生物量相关生长关系表现为无相关生长关系（4月20日-5月10日）—异速生长（5月10日-6月15日）—等速生长（6月15日-30日）—异速生长（6月30日-7月30日）—等速生长（7月30日-8月30日）的趋势. 地上、地下和整株生物量的最优模型分别为幂函数形式（y = 0.0067x1.4303）、二次方程形式（y = 0.0005x2 - 0.0141x + 0.4380）和指数函数形式（y = 0.3364e0.0437x），经检验地上、地下和整株生物量最优模型均基本符合建模标准. 本研究表明林下蚊子草在不同生长阶段地上和地下生物量的分配规律及其相关生长关系是不一致的，这是植物对环境适应的结果，保证其在不同环境条件下维持正常的营养生长和生殖生长. （图3 表4 参43）