The allocation of anatomical traits determines the trade-off between fine root resource acquisition-transport function.

Cortex radius (CR) and stele radius (SR) are important functional traits associated with the nutrient acquisition and transport functions of fine roots, respectively. However, for developmental and anatomical reasons, the resource acquisition-transport relationship of fine roots is expected to be different for different root orders. To address this issue, critical fine root anatomical traits were examined for the first three orders of roots of 59 subtropical woody plants. Designating the most distal fine roots as order one, SR scaled isometrically with respect to root radius (RR) (i.e., SR ∝ RR1.0) in the three root orders, whereas CR scaled allometrically with respect to RR (i.e., CR ∝ RR>1.0) with the numerical values of scaling exponents increasing significantly with increasing root orders thereby indicating a disproportional increase in CR with increasing root orders. There were also differences between normalized root tissue (CR/RR and SR/RR) and RR in different root orders. A negative isometric relationship (i.e., SR/RR ∝ RR-1.0) existed between SR/RR and RR in three order roots, whereas the allometric exponent between CR/RR and RR increased with root order (from 0.88 to 1.55). Collectively, the data indicate that root anatomical and functional traits change as a function of RR and that these changes need to be considered when modeling fine root resource acquisition-transport functions.

Mazusdanxiacola (Mazaceae), a distinct new species endemic to Danxia landform in Jiangxi Province, eastern China.

Mazusdanxiacola, a new species endemic to Danxia landform in east Jiangxi Province, eastern China, is described and illustrated. The systematic placement of this new species was confirmed by molecular phylogenetic analyses based on four plastid markers (matK, rbcL, rps16 and trnL-trnF) and nuclear ribosome ITS sequence, and its specific relationships within Mazus were discussed. Morphologically, the new species is clearly different from other Mazus species by having a series of uncommon traits, i.e., annual habit, without stolons and basal leaves, single, erect and unbranched stems, long petiolate leaves abaxially grayish green to silver gray, truncate to broadly cuneate leaf bases, racemes extremely elongated up to 35 cm long, white corolla, and palate densely covered by conspicuous clavate gland-like hairs. The new species is assigned to Critically Endangered (CR) according to the IUCN Red List Categories and Criteria.

[Identification of the potential distribution area of Cunninghamia lanceolata in China under climate change based on the MaxEnt model]. / 基于MaxEnt模型预测气候变化下杉木在中国的潜在地理分布.

Based on the distribution records of Cunninghamia lanceolata, we used the maximum Entropy (MaxEnt) model and geographic information system (GIS) methods, combined with environmental factors such as climate and terrain, to predict the potential distribution areas suitable for C. lanceolata under current and future climate scenarios. The results showed that annual precipitation was the most important factor driving the distribution of C. lanceolata. Under the current climate scenario, the total area of suitable for C. lanceolata growth was about 3.28 million km2, accounting for about 34.5% of the total land area of China. Among all the suitable areas, the lowly, intermediately, and highly suitable areas accounted for 18.3%, 29.7% and 52.0% of the total, respectively. Under future climate scenarios, the suitable area of C. lanceolata would increase, showing a clear trend of northward expansion in China. A concentrated and contiguous distribution region highly suitable for C. lanceolata would appear in the humid subtropical areas of southern China. The model was tested by the receiver operating characteristic curve (ROC). The average area under the curve of ROC of the training set was 0.91, showing high reliability.