The root of Moso bamboo (Phyllostachys edulis (Carrière) J. Houz.) develops extremely rapidly at seedling phase and is highly sensitive to water content in soil, but its response patterns and adaptation strategies of its root to drought are little known. The aim of this study was to investigate the response of root morphology and architecture of Moso bamboo to drought at seedling phase and then to explore the drought adaptation strategies of its root. One-year-old potted seedlings of Moso bamboo were planted under three drought treatments (control, moderate drought and severe drought) for three months. Seedling growth, specific root length (SRL), root architecture (fractal dimension (FD), root branching angle (RBA) and root topological index (TI)) and non-structural carbohydrate (NSC) concentrations in roots were measured every month. The results are as follows: (i) The dry weight of root and shoot decreased significantly under drought stress. (ii) The SRL decreased under drought stress in the early duration (the first month), and then increased in the late duration (the third month). Both FD and RBA decreased, while TI and the concentrations of NSCs increased under drought stress. (iii) The NSC concentrations were positively correlated with SRL and TI, but exhibited an inverse relationship to FD and RBA. Our results indicated that Moso bamboo seedlings formed a “steeper, simpler, expensive (low SRL and high TI)” root architecture to adapt to a short-term drought (one month), and formed a “cheaper (high SRL)” root to adapt to a long-term drought (three months). Increase of NSC concentrations supported the root architecture plasticity to some extent.

Previous studies have shown that biochar fertilization has profound effects on plant and fine root growth, but there is a lack of studies on how changes in plant and soil stoichiometry by biochar fertilization influence plant growth and root morphology. We investigated the effects of biochar fertilization on biomass, root morphology, plant nutrient concentrations, and the stoichiometry of plants and soil in a greenhouse experiment with Pinus massoniana (Lamb.) (PM) and Cunninghamia lanceolata (Lamb.) Hook. (CL) throughout the 2017 growing season immediately following biochar fertilization application. Four levels of biochar treatment were used, i.e., addition rates of 0 (control), 5 (low biochar), 10 (medium biochar), and 20 t ha⁻¹ (high biochar). Biochar fertilization had no effect on biomass, fine root length, or fine root surface area. Biochar treatment, however, had significant effects on nutrient levels and their stoichiometry in both plants and soil. Detrended correspondence analysis suggested that increases in soil C:N, soil C:P, and soil N:P were associated with increases in plant nutrient levels, especially P concentration. Our results indicate that biochar fertilization prioritizes enhancing plant and soil nutrients over increasing height and diameter in the first growing season. A higher biochar fertilization dosage has a major influence on root morphology for PM and on P concentrations in the plant and soil for CL, probably through different growth characteristics and nutrient resorption rates. Further studies, particularly those considering long-term effects, are necessary before general recommendations regarding biochar application should be given.

The aim of this work was to study the changes in the BVOCs emission rates and physiological mechanistic response of Pinus massoniana saplings in response to drought stress. Drought stress significantly reduced the emission rates of total BVOCs, monoterpenes, and sesquiterpenes, but had no significant effect on the emission rate of isoprene, which slightly increased under drought stress. A significant negative relationship was observed between the emission rates of total BVOCs, monoterpenes, and sesquiterpenes and the content of chlorophylls, starch, and NSCs, and a positive relationship was observed between the isoprene emission rate and the content of chlorophylls, starch, and NSCs, indicating different control mechanism over the emission of the different components of BVOCs. Under drought stress, the emission trade-off between isoprene and other BVOCs components may be driven by the content of chlorophylls, starch, and NSCs. Considering the inconsistent responses of the different components of BVOCs to drought stress for different plant species, close attention should be paid to the effect of drought stress and global change on plant BVOCs emissions in the future.

Leaf nitrogen (N) and phosphorus (P) stoichiometry at a large geographical scale is the result of long-term adaptation to the environment. Therefore, the patterns of leaf N and P spatial distributions and their controlling factors represent an important issue in current ecological research. To explore the leaf stoichiometry of Chinese fir at a national level, we conducted a meta-analysis based on the dataset of the leaf nitrogen (N) and phosphorus (P) concentrations and the N:P ratio from 28 study sites across China. For all of the age groups considered, the average concentrations of the leaf N and P concentrations and the N:P ratio were 11.94 mg g⁻¹, 1.04 mg g⁻¹, and 12.93, respectively. Significant differences were found in the leaf P concentration and N:P ratio between the five age groups, while the differences in the leaf N concentration between the groups were not significant. Linear fitting results indicated that the leaf P concentration decreased, and the leaf N:P ratio increased with the increase of the MAT (mean annual temperature) and soil N concentration. Redundancy analysis (RDA) revealed that the first axis, with an explanatory quantity of 0.350, indicated that the MAT (mean annual temperature), soil nitrogen concentration and stand age had a good relationship with the leaf P concentration and N:P ratio, while the second axis, with an explanatory quantity of 0.058, indicated that the leaf N concentration was less affected by the environmental factors. These results demonstrate that the leaf P concentration and N:P ratio are affected by the stand age, an uneven distribution of the heat and soil nutrient concentration status, and N, as the limiting element, remaining relatively stable. Overall, our findings revealed the response of leaf stoichiometric traits to environment change, which benefits the management of Chinese fir plantations.

In 2008, an unexpected and severe ice storm affected the forest of southern China. This storm caused damage in regeneration of an important dominant tree, Schima superba (Gugertree). To study this damage, we set up permanent monitoring plots in an ice-storm-damaged subtropical evergreen broad-leaved secondary forest dominated by S.superba in Jianglang Mountains, China. We surveyed the damage to all trees with a minimum basal diameter of 4 cm and monitored their growth for 6 consecutive years. We analyzed the degrees and types of damage for S.superba and their relationships with resprouting characteristics. The results revealed that the main damage types of S.superba were decapitation (45.45%) and uprooting (28.41%). The distribution percentage for both decapitated and uprooted trees were commonly highest in the range of 10–16 cm basal diameter (BD) size class. A great number of individuals sprouted vigorously after the storm. The mean total sprout number and sprout biomass per tree for S.superba varied by tree BD size class. During the first three years after the ice storm, decapitated trees of larger BD classes produced more sprouts per tree than trees of smaller BD classes. However, the opposite trend was seen in uprooted and leaning trees. There was a trade-off between the total number and length of the sprouts. The difference of mean sprouts number and biomass per tree with size class was mainly related to the damage types. As the recovery progressed since the ice storm, the number of sprouts and sprout biomass in uprooted trees was found mainly on the middle trunk sections of uprooted trees, but in the upper sections of decapitated trees. After six years, the mean number of sprouts per tree, on different parts of the tree and for the three types of damaged trees all declined; however, sprout biomass per tree all increased. The mean number of sprout and sprout biomass per tree on different sections for decapitated trees was always highest over time since the storm. Our study will help to provide data on resprouting ability to develop a predictive model for resprouting.

Increasingly frequent extreme droughts threaten forest vegetation and highlight the need to identify drought-tolerant germplasm. To support conservation and cultivation of Illicium lanceolatum, we investigated ecotypic differences in photosynthetic responses to short-term drought and rewatering under varying light intensity. One-year-old seedlings from four I. lanceolatum ecotypes originating from the Zhejiang (Lin’an, LA; Kaihua, KH), Jiangxi (Wu’ning, WN), and Fujian (Nan’ping, NP) provinces in China were subjected to drought stress by withholding irrigation and subsequent rewatering. Photosynthesis–light response curves were measured before drought; 2, 4, and 7 days after the last watering; and following rewatering. Short-term drought significantly affected photosynthetic traits in an ecotype-dependent manner. Maximum net photosynthetic rate, light saturation point, light compensation point, and apparent quantum yield increased during drought, indicating enhanced utilization of both high and low light. After rewatering, stomatal conductance increased significantly in the WN and KH ecotypes but declined in the NP ecotype when compared with those under the initial water supply. Instantaneous water use efficiency (A/E) recovered rapidly in all ecotypes and exceeded pre-drought levels. Under light intensity above 1500 µmol·m⁻²·s⁻¹, stomatal conductance exhibited a significant nonlinear relationship with water use efficiency. Overall, these physiological responses indicate that I. lanceolatum is moderately drought-tolerant and exhibits mild sensitivity to soil water variation. The WN and KH ecotypes showed superior improvement in water use efficiency under drought and high light, suggesting their potential for breeding drought-resistant cultivars and for afforestation in drought-prone environments.