摘要：
Investigations on the impact of drought stress on the reproductive growth of C. oleifera have been relatively limited compared to the extensive research conducted on its nutritional growth. To study the effects of drought stress on the growth and development of C. oleifera flower buds, we investigated the effects of drought stress on the bud anatomical structure, relative water content, relative electrical conductivity, antioxidant enzyme activity, osmoregulation substance content, and hormone contents of C. oleifera using 4-year-old potted plants ('Huaxin' cultivar) as experimental materials. We observed C. oleifera flower bud shrinkage, faded pollen colour, shortened style length, decreased relative water content, increased relative electrical conductivity, and decreased pollen germination rate under drought stress. As the stress treatment duration increased, the malondialdehyde (MDA), soluble sugar (SS), soluble protein (SP), and proline (Pro) contents, as well as peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities increased. Moreover, the levels of the plant hormones indole acetic acid (IAA) and cytokinin (CTK) increased, whereas those of salicylic acid (SA) and jasmonic acid (JA) decreased, and those of abscisic acid (ABA) and gibberellin a(3) (GA(3)) first increased and then decreased. Compared to the control group, the drought treatment group exhibited stronger antioxidant capacity, water regulation ability, and drought stress protection. These results indicate that C. oleifera is adaptable to drought-prone environments. The results of this study provide a theoretical basis for the evaluation of drought resistance in C. oleifera, as well as the development of water management strategies for cultivation.
摘要：
Camellia oleifera Abel., which produces fruits of high comprehensive utilization value, is an important woody oil tree in China. ZEITLUPE (ZTL) is a blue light receptor and clock component protein that is involved in various physiological and biochemical processes. However, the expression pattern and function of C. oleifera ZTL (CoZTL) remain unclear. In this study, the coding sequence of the CoZTL gene was isolated and the protein function was explored using bioinformatics and expression analyses and heterologous expression techniques. The results showed that the CoZTL protein was highly conserved during evolution and was on the same branch of the evolutionary tree as the ZTL proteins from Ipomoea nil and Nicotiana attenuata. CoZTL was mainly expressed in the fruit shells and stems of C. oleifera, and its expression level fluctuated greatly during flower bud development. Transgenic CoZTL-overexpressing Arabidopsis plants showed delayed flowering under long-day conditions as well as light-dependent promotion of hypocotyl elongation. Furthermore, yeast two-hybrid library screening revealed that seven C. oleifera proteins (CoAAT, Co & beta;-GAL, CoLAT52-like, CoCAR4-like, CoAO, CoUQCC1, and CoADF 2) interacted with CoZTL. Our results indicate that CoZTL plays an important role in C. oleifera flowering and hypocotyl growth.
摘要：
Wood anatomy and plant hydraulics play a significant role in understanding species-specific responses and their ability to manage rapid environmental changes. This study used the dendro-anatomical approach to assess the anatomical characteristics and their relation to local climate variability in the boreal coniferous tree species Larix gmelinii (Dahurian larch) and Pinus sylvestris var. mongolica (Scots pine) at an altitude range of 660 m to 842 m. We measured the xylem anatomical traits (lumen area (LA), cell wall thickness (CWt), cell counts per ring (CN), ring width (RW), and cell sizes in rings) of both species at four different sites Mangui (MG), Wuerqihan (WEQH), Moredagha (MEDG) and Alihe (ALH) and investigated their relationship with temperature and precipitation of those sites along a latitude gradient. Results showed that all chronologies have strong summer temperature correlations. LA extremes were mostly associated with climatic variation than CWt and RWt. MEDG site species showed an inverse correlation in different growing seasons. The correlation coefficient with temperature indicated significant variations in the May-September months at MG, WEQH, and ALH sites. These results suggest that climatic seasonality changes in the selected sites positively affect hydraulic efficiency (increase in the diameter of the earlywood cells) and the width of the latewood produced in P. sylvestris. In contrast, L. gmelinii showed the opposite response to warm temperatures. It is concluded that xylem anatomical responses of L. gmelinii and P. sylvestris showed varied responses to different climatic factors at different sites. These differences between the two species responses to climate are due to the change of site condition on a large spatial and temporal scale.
摘要：
Abstract Arbuscular mycorrhizal fungi (AMF) symbiosis plays essential roles in shaping rhizosphere soil available phosphorus (P) and organic P mobilization. However, current methods for assessing soil P often do not fully consider the potential role of arbuscular mycorrhizal fungi (AMF) in supplying biologically‐based phosphorus (BBP) to Eucalyptus. This study aims to investigate the effects of AMF on the soil BBP of Eucalyptus plantations and which species prefer to translocate them in phosphorus‐deficient soils. Rhizosphere soil samples of Eucalyptus plantations (in south China) exhibiting different ages (varying between 1 to 12 years) were selected to investigate the evolution of AMF and BBP in soils, as well as their interaction mechanism. The impacts of eight AMF families on BBP were investigated in rhizosphere soil. All BBP contents are significantly positively correlated with Olsen P in the rhizosphere soil of Eucalyptus plantations (p < 0.01). The BBP in soil was notably influenced by AMF diversity, while AMF richness showed little effect on BBP. The abundance of Glomeraceae taxa showed a positive correlation with BBP and a negative correlation with Paraglomeraceae. In contrast, the relative abundance of Glomeraceae was higher in older plantations (including Archaeosporaceae, Claroideoglomeraceae). From the above results, we concluded that different species of the AMF modulated their mycorrhizal traits by improving BBP uptake in the rhizosphere soil. AMF groups (such as Glomeraceae, Archaeosporaceae, Claroideoglomeraceae) should be introduced or amplified at the beginning of planting to promote the uptake and utilization of bioavailable P in Eucalyptus plantations. This study will deepen our understanding of AMF for effective BBP utilization in Eucalyptus plantations.
摘要：
This paper aims to reveal the effects of multi-generational succession of eucalyptus on soil fertility, organic structure and biological properties. Soil samples were collected from eucalyptus plantations of different stand ages (5, 11, 17 and 21 years old) in a typical area in south Asia, soil organic fraction structure and content characteristics were investigated using Fourier transform infrared (FTIR), and structural equation modelling (SEM) was used to explore influences of soil fertility, enzyme activity and organic fraction on stand biomass. FTIR analysis showed that 11 infrared absorption peaks existed in the soils of this study area, attributed to silicates, aromatics, carbonate ions, sugars, esters, polysaccharides, aliphatic hydrocarbons and phenolic alcohols. Combined with the results of peak area integration, the content of esters, aromatics and phenolic alcohols was significantly higher in 17- and 21-year-old stand soils than in control soils. The results of SEM showed that organic components were negatively related (p < 0.01) to enzyme activity and biomass, with standardized coefficients of 0.53 and 0.49, respectively. In summary, multi-generation succession of eucalyptus trees can change the structure of soil organic functional group composition and promote the enrichment of aromatic and phenolic alcohol functional groups. Such changes can directly inhibit the increase in eucalyptus biomass and indirectly negatively affect biomass by inhibiting enzyme activity.
摘要：
Accurate, detailed urban forest mapping contributes to ecological status monitoring and formulating sustainable development policies in cities worldwide. However, accurate urban forest identification in southern Chinese cities is challenging when samples are insufficient because of high fragmentation and the influence of mountain shadows and cloudy weather. Therefore, this study combined the advantages of transfer, deep, and ensemble learning to propose a VGG16-UNet++&Stacking algorithm for urban forest mapping in heavily urbanized areas based on the Sentinel dataset. Initially, the algorithm mined deep features of an image by pre-training the convolutional layer. Then, the deep feature set was fed into ensemble learning for classification to improve accuracy and robustness. The classification results showed that the VGG16-UNet++&Stacking had an overall accuracy (OA) of 95.87% and a Kappa coefficient of 0.9481. Furthermore, the user accuracy (UA) of the forest was 97.94%. The OA of the method in this study was improved by 2.2% and 3.83% compared with that of UNet++ and random forest (RF), respectively. Compared to that of UNet++, the results showed a modest improvement in OA for the VGG16-UNet++&Stacking method; VGG16-UNet++&Stacking is more effective in eliminating cloud influence, a feature that UNet++ lacks.
通讯机构：
[Wenfang Gong; Deyi Yuan] K;Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees of the Ministry of Education and Key Laboratory of Non-Wood Forest Products of the Forestry Ministry, Central South University of Forestry and Technology , Changsha, Hunan 410004, China
摘要：
Camellia oil extracted from the seeds of Camellia oleifera Abel. is a popular and high-quality edible oil, but its yield is limited by seed setting, which is mainly caused by self-incompatibility (SI). One of the obvious biological features of SI plants is the inhibition of self-pollen tubes; however, the underlying mechanism of this inhibition in C. oleifera is poorly understood. In this study, we constructed a semi-in vivo pollen tube growth test (SIV-PGT) system that can screen for substances that inhibit self-pollen tubes without interference from the genetic background. Combined with multi-omics analysis, the results revealed the important role of galloylated catechins in self-pollen tube inhibition, and a possible molecular regulatory network mediated by UDP-glycosyltransferase (UGT) and serine carboxypeptidase-like (SCPL) was proposed. In summary, galloylation of catechins and high levels of galloylated catechins are specifically involved in pollen tube inhibition under self-pollination rather than cross-pollination, which provides a new understanding of SI in C. oleifera. These results will contribute to sexual reproduction research on C. oleifera and provide theoretical support for improving Camellia oil yield in production.
