Compression wood (CW) in gymnosperm brings great difficulties to wood industry using wood as raw materials since CW presents special wood structure and have different physical and chemical properties ...from those of normal wood (NW). Chinese fir (
) is widely distributed in China. However, global transcriptome profiling of coding and long non-coding RNA in response to compression stress has not been reported in the gymnosperm species. In this study, we revealed that CW in Chinese fir exhibited distinct morphology and cytology properties compared with those of NW, including high lignin content, thick and round tracheid cells. Furthermore, we combined both PacBio long-read SMRT sequencing (Iso-Seq) and Illumina short-read RNA-Seq to reveal the transcriptome in stem-differentiating xylem (SDX) under different time points (2, 26, and 74 h) upon compression stress in NW, CW, and OW (opposite wood), respectively. Iso-Seq was successfully assembled into 41,253
full-length transcriptome reference (average length 2,245 bp). Moreover, there were striking differences in expression upon compression stress, which were involved 13 and 7 key enzyme genes in the lignin and cellulose synthesis, respectively. Especially, we revealed 11 secondary growth-related transcription factors show differential expression under compression stress, which was further validated by qRT-PCR. Finally, the correlation between 6,533 differentially expressed coding genes and 372 differentially expressed long non-coding RNAs (lncRNAs) indicates that these lncRNAs may affect cell wall biogenesis and xyloglucan metabolism. In conclusion, our results provided comprehensive cytology properties and full-length transcriptome profiling of wood species upon compression stress. Especially we explored candidate genes, including both coding and long non-coding genes, and provided a theoretical basis for further research on the formation mechanism of CW in gymnosperm Chinese fir.
Introduction
The longitudinal section cell morphology of Chinese fir roots was studied to better understand the relationship between root structure and root function.
Materials
In this study, the ...adjusted microwave paraffin section method and the selected two sample transparency methods were used to process the Chinese fir roots and combined with the laser scanning confocal microscopy (LSCM) technique, the morphology of Chinese fir roots longitudinal section can be clearly observed in a short time. At the same time, the observation effect of the longitudinal section cell morphology of the LSCM image of the thick section of the Chinese fir roots and the ordinary optical imaging of the thin section was analyzed and compared.
Results and Discussion
The results showed that: (1) There were apparent differences in the observation effect of cell morphology in longitudinal sections of Chinese fir roots obtained using various treatment methods. Under LSCM, the section with a thickness of 20 μm generated by the microwave paraffin section technique displayed complete cell morphology and clear structure in the root cap, meristem zone, and elongation zone. The overall imaging effect was good; the thickness was 0.42–1.01, 0.64–1.57, and 0.95–2.71 mm, respectively. The cell arrangement in maturation zone cells was more regular. (2) Compared to the ordinary optical imaging of thin sections, the thick sections of roots made by the microwave paraffin section method shortened the time to obtain high-quality sections to ensure the observation effect. Therefore, adopting the microwave paraffin cutting approach to produce thicker root sections under LSCM allows for rapid observation of the cell morphology in longitudinal sections of Chinese fir roots. The current study provides the efficient operation procedure for the microscopic observation technology of the longitudinal section of Chinese fir roots, which is not only beneficial to reveal the relationship between the root structure and function from the microscopic point of view but also provides a technical reference for the anatomical study of other organs and the observation of the longitudinal section cell morphology of plant roots with similar structural characteristics.
Studies on the extent to which households are affected by earthquake and their varying degree of dependence on forest resources, particularly reliable and comprehensive ones, are very rare. This ...study assessed the types of shocks faced by the earthquake-hit households and the change in timber and firewood use patterns by them before and after the occurrence of devastating Gorkha earthquake-2015 in Nepal. The study used household level panel dataset (n = 99 in 2008 and 2018) collected using a modified version of household survey questionnaire developed by Centre for International Forest Research (CIFOR) for studying the poverty-environment network. Separate random effect models are employed to identify the factors that influence the collection of firewood and timber by theearthquake shock exposed households. The results reveal that the households exposed to earthquake lost significant number of livestock and labor, land and other assets. Regression results show that there was a positive and significant association between firewood collection and the households exposed to earthquake, and there was a negative and significant association with migration. Similarly, there was significant increase in timber wood collection but the magnitude of increment was very small. The access control for timber collection, limited assets holding and other access constraints limited their resilience through timber collection. The study highlights the importance of targeted intervention that helps not only to provide access to land and livestock to the affected communities but opens other income-generating options to improve their wellbeing and to invest in human capitals for enhancing their resilience.
•Empirically explored the collection pattern of firewood and timber after the Nepal’s earthquake-2015•Results are based on the unique panel dataset analyzed using a random-effect model.•More the households are exposed to severe shock; more would be the firewood collection.•Non-migrated households collected a significantly larger quantity of firewood compared to migrated households.•Controlled access on timber collection to the earthquake-hit households limits their resilience capacity.
The distribution in tree biomass and understorey vegetation and annual biological and geochemical cycling of total nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) were ...measured in young, middle-aged and mature plantations (8-, 14- and 24-years old) of Chinese fir (
Cunninghamia lanceolata (Lamb.) Hook.) in southern China. Although >98% of nutrients occurred in the soil, soil nutrient content decreased with plantation age. Nutrient outputs from the soil exceeded inputs in stands of all ages but the net soil nutrient loss increased significantly for N, P and Ca with plantation age. Comparison of nutrient fluxes showed that the smallest (and hence limiting for nutrient cycling) fluxes were litter decomposition in the young plantation in contrast to canopy fluxes (apart from for Mg) in the middle-aged and mature plantations. Nutrient use efficiency, release of nutrients from litter decomposition and nutrient return, particularly in litterfall, increased significantly with plantation age. These results suggest that, as stand age increases, nutrient cycling in Chinese fir plantations is increasingly dominated by biological processes and becomes less dependent on external nutrient sources in rainfall and the soil. It therefore appears that prolonging the rotation length of Chinese fir plantations by approximately 5 years could be beneficial for maintaining the soil nutrient status for successive plantings.
The study on the function and sequence of PHR1 (Phosphate Starvation Response gene 1) gene, which plays a central role in plant phosphorus (Pi) signal regulatory network, is of great significance to ...further study response mechanisms to Pi deficiency. In this work, the previously selected Pi-efficient Chinese fir clone M32 was used as research material to obtain the full-length sequence of ClPHR1 transcription factors in Chinese fir by RACE (Rapid Amplification of cDNA Ends) full-length cloning technique, and the structure, function and subcellular localization of ClPHR1 gene encoding protein were analyzed. The temporal and spatial expression characteristics of ClPHR1 transcription factors in Chinese fir under low Pi stress were also analyzed, and the overexpression of ClPHR1 gene in transgenic Arabidopsis thaliana was obtained to verify the function of ClPHR1 gene under low Pi stress. The results showed that the length of the ClPHR1 gene obtained by rapid amplification of cDNA ends technique was 1954 bp, of which 1512 bp was an open reading frame. ClPHR1 was predicted to be an unstable hydrophilic protein with only one possible transmembrane domain. The ClPHR1 gene had a highly conserved MYB-CC domain, which is similar to the PHR1 gene of other plants. Phylogenetic tree analysis showed that the sequence had high homology with PHR1 genes in the Prunus species. The ClPHR1 was expressed in all organs of Chinese fir, with the highest expression in the roots, followed by the leaves with the lowest expression in stems. ClPHR1 expression in roots was reduced dramatically at the beginning of Pi stress treatment and followed by an increase at 7days; in leaves, it increased dramatically at the beginning of Pi starvation treatment and showed a decreasing trend after 3 days; in stems, the expression level of ClPHR1 increased after 7 days of Pi stress treatment. The transient expression vector was introduced into plant cells, and it was found that ClPHR1 was located in the nucleus and was a MYB-CC transcription factor expressed in the cell nucleus. The ClPHR1 overexpression vector was constructed, and then introduced into Arabidopsis thaliana by agrobacterium infection inflorescence method. The expressions of Pi transporter genes, AtPHT1;1, AtPHT1;2, AtPHT1;8 and AtPHT1;9, was significantly higher in the overexpressing strain than that in the wild type strain. The results suggest that the ClPHR1 transcription factor could regulate the regulation of downstream Pi transporter gene and increase Pi utilization efficiency of the Chinese fir under Pi stress.
Seed lots of pine species are composed of viable, dead-filled and empty seeds, and the success of complete sorting of dead-filled seeds using the conventional method (Incubation, Drying and ...Separation in water) is difficult to achieve; leaving a considerable scope for upgrading the sorting efficiency. The objective of this study was to evaluate the prospect of sorting viable and dead-filled seeds of pine species using Near Infrared (NIR) spectroscopy. To demonstrate this, dead-filled and viable seeds of Mason’s pine, slash pine and loblolly pine were incubated in moist medium for three days, dried for six hours and scanned by XDS Rapid Content Analyzer from 780–2500 nm. Orthogonal Projection to Latent Structure-Discriminant Analysis was used to develop discriminant models for each species separately and for all species combined. The results showed that the sensitivity (the model’s ability to correctly classify members of a given class) and the specificity (the model’s ability to reject non-members of a given class) were 100% for each species model and 98%–99% for combined species model. The overall classification accuracy was 100% and 99% for individual species and combined species models, respectively. The absorption band in the 1870–1950 nm with a major peak at 1930 nm, which is related to water, was responsible for discrimination as dead-filled seeds dried quicker than viable seeds during the drying process. Our study is the first attempt to simultaneously discriminate dead-filled and viable seeds of pines by NIR spectroscopy. The results demonstrates that a global calibration model of seed lots of several pine species can be equally effective as the individual species model to discriminate viable and dead-filled seeds by NIR spectroscopy, thereby ensuring precision sowing (also known as single seed sowing) in nurseries.
The amounts of litter produced and nutrients returned play a fundamental role in the productivity and biogeochemical and nutrient cycling of forest ecosystems. We monitored annual litterfall ...production, nutrient return, and monthly dynamics over a one-year period in Chinese fir plantations aged 10, 22, and 34 years. Our objective was to quantify litterfall and nutrient return over a complete harvest rotation of Chinese fir. Annual litterfall production increased with stand age and was recorded as (3,294.6 ± 360.4), (3,733.9 ± 211.2), and (4,876.1 ± 212.8) kg ha⁻¹a⁻¹in stands aged 10, 22 and 34 years, respectively. Total litter production was significantly greater in the stand aged 34 years than in the stand aged 10 years (p < 0.05). With the exception of miscellaneous components, needle litterfall constituted the highest proportion (27.5–43.6 %), followed by branches/twigs (9.5–16.6 %). In all three plantations, annual total nutrient return to soil was in the order of C (1,119.95–2,709.05 kg ha⁻¹ a⁻¹) > N (39.32–62.04 kg ha⁻¹ a⁻¹) > K (15.95–22.44 kg ha⁻¹ a⁻¹) > P (1.30–1.63 kg ha⁻¹a⁻¹). C, N, K and P input to soil was significantly lower in the 10-year-old stand in comparison to the 22- and 34-year-old stands (p < 0.05). Litterfall production and nutrient return (C, N and K) followed similar patterns, and C and N input to soil was significantly related to litterfall production (needle, branch and total litterfall). C, N, P and K input to soil and total litterfall production were mainly driven by needle litterfall.
Changting has been promoted by the Chinese government as a demonstration for the soil and water conservation works in recent years. As the experience in Changting is now being explored and summarized ...and will be further promoted to the nation, it is important to understand the factors affecting the vegetation restoration process. Random forest and multiple linear regression approaches were applied to investigate the influential factors and their relative importance on the dynamic change of vegetation coverage of Changting during the period of 2000–2010. The Normalized Difference Vegetation Index (NDVI) was used to calculate Fractional Vegetation Cover (FVC) dynamics in response to topographic, climatic, infrastructure, and economic factors. The results show that overall, there was a dramatic increase in the FVC of Changting from 2000–2010. The percentage of the FVC-increased area reached 87.86% with an increase rate of 0.142. Factors such as precipitation, temperature, elevation, slope and financial investment for soil conservation were important drivers of local FVC change. Our findings reveal that climatic factors along with the strict implementation of government policies played a role in driving vegetation cover dynamics, and the continuation of implementation of soil erosion management in Changting is required.
Available P is the major growth-limiting factor in southern China where Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations are increasingly established. Planting P-efficient clones is a ...viable option to enhance productivity of Chinese fir plantations. Two Chinese fir clones with high P efficiency (M1 and M4) were chosen as the research materials and their adaptive responses to low P stress were examined. The increment in root morphological traits and biomass production of these clones was measured by a sand culture experiment with a heterogeneous P supply. For both clones, P starvation resulted in significantly higher root surface area and root volume but not root length. For clone M4, the mean root diameter was also larger under P deficiency than under normal P supply. Interestingly, the root morphological traits varied substantially within the same root system where the starved roots had higher values for all morphological traits than the nonstarved ones. Phosphorus starvation did not affect shoot and root biomass or the root to shoot ratio, but the whole-plant biomass increment was large under P deficiency for clone M4. In conclusion, the adaptation to low P stress in these clones is attributed to increased P acquisition and utilization efficiencies.
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