A systematic study was conducted on the flowering biological characteristics of Bambusa emeiensis L. C. Chia & H. L. Fung to clarify the flowering rhythm of bamboo species under artificial cultivation conditions, so as to provide a scientific basis for the effective implementation of cross-breeding of Bambusa emeiensis.

Two clonal lines of Bambusa emeiensis, DTW and JJS, transplanted in Hangzhou were used as research materials. The forest appearance and flowering phenology of the two clones were observed via field investigation. The morphological structure of floral organs was observed and recorded by dissecting spikelets. Pollen viability was detected using the iodine-potassium iodide (I₂ - KI) staining method and in vitro germination assay, while stigma receptivity was examined with the benzidine-hydrogen peroxide method. The breeding characteristics of the two clones were analyzed by estimating the pollen-ovule ratio (P/O).

1) The two clones of B. emeiensis L. C. Chia & H. L. Fung exhibited identical flowering periods, with full bloom from mid-May to early August, and a few florets continued to open for another two weeks thereafter; 2) The spikelets of the DTW clone are purple - brown overall, while those of the JJS clone are purple-brown with a slight green tint. The anthers of the DTW clone are 5.48±0.55 mm long and yellowish-brown, while those of the JJS clone are 4.51±0.32 mm long and bright red; 3) The pollen viability and germination rate of both the DTW and JJS clones reach their peaks when the anthers are completely exposed. The optimal pollen viability is achieved in May and July, with the proportions of strong pollen viability being 75.2% and 79.2% respectively. The optimal germination rates are achieved in June and July, with the proportions of good germination being 4.3% and 4.9% respectively; 4) Both clones exhibited the strongest stigma receptivity during anther dehiscence; 5) Under artificial pollination, the seed-setting rate reached 4.00% for DTW and 2.67% for JJS, while no seed-setting was observed under natural pollination conditions in either their original habitats or transplanted habitats.

The flowering characteristics of the two clones of B. emeiensis L. C. Chia & H. L. Fung are different, and their flowering is not synchronized under the same environmental conditions. The DTW clone is suitable for pollination in June, while the JJS clone is suitable for pollination in July, but both clones possess a certain degree of fertility. Although the overall fertility of the two clones is relatively low, they can still serve as breeding materials.

This study aimed to explore the effects of stratification treatment on breaking the dormancy of Celtis sinensis seeds. The changes in nutrients, endogenous hormones and key enzyme activities during the stratification process were analyzed to clarify its hibernation release mechanism and find the best method for breaking seed dormancy.

Three treatment methods were adopted for Celtis sinensis seeds: variable temperature stratification, low-temperature stratification, and gibberellin combined with low temperature stratification. The physiological indicators such as soluble sugar, soluble protein, starch, crude fat, glucose-6-phosphate dehydrogenase (G-6-PDH), lipase, indole acetic acid (IAA), gibberellin (GA₃), zeatin riboside (ZR), and abscisic acid (ABA) of the seeds under different stratification stages were detected to analyze the changing trends of these physiological indicators during the stratification process.

Stratification treatments can significantly increase the germination rate of Celtis sinensis seeds. The effect of gibberellin combined with low temperature stratification treatment is the best, with a germination rate of 54.7% after 100 days of stratification. As the stratification process progresses, the trends of physiological indicators in each treatment are similar: soluble sugar increased first and then decreased, and soluble protein, starch and crude fat were decomposed continuously. The activity of lipase and G-6-PDH enzyme was enhanced continuously. IAA increased first and then decreased, ABA decreased continuously, and the contents of GA₃ and ZR increased continuously. The ratios of IAA/ABA, GA₃/ABA and ZR/ABA increased continuously. Gibberellin combined with low temperature stratification treatment showed significantly higher enzyme activity and GA₃ content in the middle and later stages of stratification compared to the other two treatments, while the ABA content was significantly lower than those of the other two treatments.

Stratification treatment effectively broke the dormancy of Celtis sinensis seeds, and the method of gibberellin combined with low temperature stratification is the best. During the stratification process, the nutrients, enzyme activities and endogenous hormone contents within the seeds are mutually transformed, jointly promoting the transition of Celtis sinensis seeds from dormancy to germination.

This study aims to explore the effects of different treatment conditions on chromosome root tip squashing, optimize the chromosome preparation method, conduct karyotype analysis of 13 Camellia species, and to provide a theoretical basis for the research on Camellia plants.

The effects of different pretreatment and dissociation conditions on chromosome slide preparation were compared to select a universally applicable method for Camellia species. Karyotype analysis of 13 Camellia species was conducted using the optimized method, yielding karyotype diagrams, parameters, and evolutionary trends for each species.

The optimized pressing method suitable for Camellia is to treat the root tips with saturated 1,4-dichlorobenzene for 6 h, then place in a 1 mol/L hydrochloric acid water bath at 60 ℃ for 15 minutes and stain with a modified carbol-fuchsin solution for 15 minutes for the conventional pressing operation. All 13 Camellia species exhibit a chromosome base number of x=15, the results of the karyotype analysis show that the karyotypes include diploid, tetraploid, hexaploid, and octoploid. Among diploids, the karyotype formula for C. semiserrata is 2n=2x=30=24m+6sm, and for the C. chekiangoleosa, it is 2n=2x=30=22m+8sm; for the tetraploid C. meiocarpa, the karyotype formula is 2n=4x=60=40m+20sm; among the hexaploid species, the karyotype formula for C. oleifera is 2n=6x=90=42m+44sm+4st, and for C. drupifera, it is 2n=6x=90=60m+26sm+4st; additionally, the karyotype formula for the octaploid C. gauchowensis is 2n=8x=120=94m+26sm. The range of asymmetry indexes for 13 Camellia species is 47.90%–64.63%, the relative length of chromosomes ranges from 2.78 to 13.59, the arm ratios range from 1.00 to 4.22, and the Lt/St ranges from 1.62 to 4.89. According to the Stebbins' karyotype classification system, the C. sinensis, C. chekiangoleosa, C. transarisanensis, and C. meiocarpa are of type 2A, C. boreali-yunnanica is type 1A, and C. osmantha is type 2C, while the remaining eight species are type 2B.

This study explored chromosome staining techniques widely applicable to Camellia, determined the chromosome numbers and ploidy levels of 13 Camellia species, and reported the karyotypes of C. transarisanensis, C. cordifolia, and C. osmantha for the first time. It provides an important reference for chromosome preparation and karyotype analysis of Camellia sinensis plants.

To explore the effects of process parameters on the cutting performance of moso bamboo during chainsaw cutting, and to establish a mechanism characterization method applicable to hollow round bamboo structures.

3-5-year-old moso bamboo was selected as the test material. A dedicated test bench for bamboo chainsaw cutting was constructed. Chainsaw specification, bamboo diameter, feed speed, and moisture content were selected as experimental factors, and peak cutting force and specific sawing energy were adopted as evaluation indices. Single-factor tests and L₉(3⁴) orthogonal array tests were conducted. In addition, the equivalent single-tooth average cutting thickness and normalized peak cutting force were introduced to carry out mechanism analysis.

The results showed that when moisture content increased from 40% to 80%, peak cutting force decreased from 48.14 to 34.29 N, and specific sawing energy decreased from 13.4 to 8.1 J/cm³. As bamboo diameter increased from 70 mm to 110 mm, peak cutting force increased from 31.18 to 52.40 N. When feed speed increased from 8 mm/s to 32 mm/s, peak cutting force increased from 26.44 to approximately 90 N, and specific sawing energy reached its relatively low value at around 24 mm/s. The orthogonal test results indicated that the factors affecting peak cutting force rank in descending order of influence magnitude as feed speed, chainsaw specification, moisture content and bamboo diameter. For specific sawing energy, the order of factor influence magnitude is chainsaw specification, feed speed, moisture content and bamboo diameter. Mechanism analysis revealed that when the equivalent single-tooth average cutting thickness increased from 0.07 mm to 0.41 mm, the peak cutting force increased from 18.66 to 101.51 N. The normalized peak cutting force exhibits a linear upward trend with the increase of equivalent single-tooth average cutting thickness, with a coefficient of determination R² of 0.702.

This study demonstrated that the peak cutting load of moso bamboo during chainsaw cutting is mainly controlled by single-tooth chip load. Moisture content, bamboo diameter, and chainsaw specification exert a modifying effect on cutting performance. The equivalent single-tooth average cutting thickness and normalized peak cutting force can be used to characterize the cutter tooth load and the stress intensity per unit effective cutting area in the chainsaw cutting of moso bamboo.

Elucidating the response of soil nutrients to long-term drought can better predict the impact of climate change on the ecosystem of moso bamboo (Phyllostachys edulis）forest in the future, and can guide the production and management practice of bamboo forest.

This study measured and analyzed the response of soil organic carbon, total nitrogen, total phosphorus content and storage, as well as their stoichiometric characteristics, to no throughfall exclusion (CK) and long-term throughfall exclusion (DR) in bamboo forests using the “ceiling method” for rain interception.

The results showed that the average value of available phosphorus content, hydrolytic nitrogen and organic carbon content, as well as the average soil C/N and C/P values in the 0-50 cm soil layer of drought soil were significantly lower than those in the control soil (P<0.05). The total phosphorus content and average pH value of drought soil were slightly lower than those in the control, while the total nitrogen content and N/P value of soil were higher than those in the control. There was no significant difference in soil nutrient content between drought and control treatments in each soil layer of 0-10 cm, 10-30 cm, and 30-50 cm. The soil pH values in all drought soil layers were lower than those in the control, with the pH value in the 10-50 cm range being significantly lower than that of the control (P<0.05). The C/P value in the 10-30 cm drought soil layer and the C/N value in the 10-50 cm drought soil layer were significantly lower than those in the control (P<0.05), while the N/P value in the 30-50 cm soil layer was significantly higher than that in the control (P<0.05). Drought has increased the “surface aggregation” phenomenon of soil nutrient content and the chemical stoichiometry. The organic carbon storage and total phosphorus storage in the 0-50 cm soil layer under drought were lower than the control, while the total nitrogen storage in the soil was higher than the control. Relevant analysis shows that the pH value of the control soil is significantly positively correlated with organic carbon, total nitrogen, and total phosphorus storage (P<0.01), while the pH value of soil under drought stress is only significantly negatively correlated with C/N and significantly positively correlated with N/P. The total nitrogen, total phosphorus, and organic carbon content in soil under drought are significantly or extremely significantly positively correlated with N/P (P<0.05 or P<0.01), while the total phosphorus content is significantly negatively correlated with C/N (P<0.05).

The soil pH value, total phosphorus, and available phosphorus content are the main influencing factors of nitrogen and phosphorus balance in soils under drought.

To analyze the variation in oil yield and oil component composition of Acer truncatum seed kernels from Horqin sandy land, and to screen for germplasm resources with high oil value.

This study takes seeds from 92 high-yielding mother trees collected from three provenances in Horqin sandy land as the research subjects. Oil extraction and determination, as well as fatty acid component and content determination, were performed. Variance analysis and correlation analysis were employed to investigate the variation in oil traits and the associations among different traits. The analytic hierarchy process (AHP) was used to conduct a comprehensive evaluation of the oil-related traits of superior trees.

1) The average oil content of the seed kernels of high-yielding superior trees of A. truncatum in Horqin Sandy Land was 46.07%, with a coefficient of variation of 6.33% and a genetic diversity index of 2.05; 2) A total of 14 fatty acid components were detected in the oils, among which linoleic acid had the highest content (33.76%), arachidonic acid had the largest coefficient of variation (48.32%), and behenic acid had the highest genetic diversity index (2.08); 3) The variance component percentage of oil content among populations and within populations was 90.16% and 9.476%, respectively, indicating that the variation mainly originated from among populations. The phenotypic differentiation coefficients for the 14 fatty acid contents ranged from 4.484% to 95.198%, with the highest coefficient observed for nervonic acid and the lowest for arachidic acid; 4) Correlation analysis indicated that oil content was significantly positively correlated with the content of arachidonic acid and stearic acid (P<0.01), and significantly negatively correlated with the content of nervonic acid (P<0.01). There are also complex correlations among the different fatty acid components; 5) The results of the AHP showed that the weight value of seed kernel oil content was 0.286, ranking first in comprehensive weight; among the fatty acid compositions, nervonic acid had the highest comprehensive weight (0.215). The comprehensive scores of the 92 superior individuals of A. truncatum ranged from 0.320 to 0.611.

The genetic diversity of A. truncatum oils in Horqin sandy land is rich, providing a material basis for the screening of oil germplasm resources; Moreover, the genetic differences in oil and nervonic acid content among different superior trees are significant, which provides the possibility for the targeted breeding of varieties with high oil and high nervonic acid content; Preliminary screening identified that the seed kernel oil content and the content of major fatty acid components in CF-6, XA-18, XA-11, CF-11, and XA-20 were all at the forefront. These strains can provide high-quality germplasm resources for the subsequent breeding of oil-related superior.

Focusing on the optimization of the adventitious bud induction system of Chamaecyparis hodginsii, a native species of Fujian, this study aims to provide theoretical support for the conservation of its germplasm resources and the development of in vitro propagation techniques.

By screening 6-BA, ZT, KT and other cytokinins, determining the most suitable implants, the best sterilization formula for implants, and the best incubation formula for adventitious bud induction, and exploring the mechanism of endogenous hormones in germination.

1) C. hodginsii is most suitable for extraction as a young, young, sprouted stem that was born in the year; 2) 75% alcohol disinfection for 10 s, 4% sodium hypochlorite disinfection for 600 s was the best disinfection formula of explants, which significantly reduced the risk of contamination; 3) The optimum culture medium for adventitious bud induction was MS + Sucrose 30.0 g/L + Agar 6.5 g/L + 0.1 mg/L KT, the rate of bud induction was 85.56%. At the same time, for the common browning problem in tissue culture of C. hodginsii, we found that the combination of AC and VC treatment had significant anti-browning effect, and the pollution rate was below 10%, effectively improving the culture efficiency; 4) The dynamic changes in the endogenous hormone levels during the process of adventitious bud induction indicate that the concentrations and ratios of IAA, ABA, GA₃, and CTK exhibit regular fluctuations. Among these, ABA and GA₃ have antagonistic effects. The balance between the ratios of IAA/ABA and CTK/IAA is the core mechanism regulating the bud germination of C. hodginsii. The period of 7-14 days is when the concentrations of IAA and the ratios of IAA/ABA, CTK/IAA reach their peak levels, making it a critical stage for the bud germination of C. hodginsii. During this period, the synergistic action of these hormones collectively contributes to their ability to adapt to the environment and promote growth and development.

This study has preliminarily established a low-pollution adventitious bud induction system for C. hodginsii, clarified the impact of different cultivation conditions on the content of endogenous hormones, and revealed the regulatory rules of endogenous hormones in the process of adventitious bud induction.

To explore the critical periods and occurrence patterns of embryo abortion during distant hybridization among apricot, plumcot, and peach, and to provide a theoretical basis and practical guidance for embryo rescue methods in Rosaceae stone fruit trees.

Twelve distant hybrid combinations were designed using apricot, plumcot, and peach as female parents. Following controlled artificial pollination, the developmental progression of young fruits was monitored, fruit size and fruit set rates at different developmental stages were recorded. The survival time of immature embryos was assessed using fluorescent staining. Viable immature embryos were subjected to bud induction, proliferation, and rooting cultures. Different plant growth regulator combinations were evaluated to establish an effective immature embryo rescue system for Rosaceae stone fruit trees.

Fruit development and immature embryo survival time in distant hybridization of Rosaceae stone fruit trees were significantly influenced by the female parent species. In hybrid combinations with common apricot or kernel apricot, plumcot, and peach, common almond, or almond as female parents, fruit growth ceased at 12, 6, and 31 days after pollination, respectively, and fruit drop began at 21, 18, and 38 days after pollination. Distant hybrid young fruits of Rosaceae stone fruit trees commonly exhibited prevented transverse diameter growth, occurring in 48.3%-69.0% of cases compared with compatible pollination controls. In addition, prevented vertical diameter growth was observed in young fruits of four combinations such as ‘Fengweimeigui’ × ‘Xiaobaixing’, with an incidence of 52.8%-55.9%, while prevented side diameter growth was noted in young fruits of ten combinations such as ‘Zhongren 3’ × ‘Jinbian 1’, occurring in 47.2%-74.3% of cases relative to controls. Seven hybrid combinations, with ‘Longwangmao’, ‘Fengweimeigui’, ‘Zhongyoutao 4’, and ‘Shantao 1’ as female parents, showed fertilization timing similar to that of compatible controls, whereas the remaining combinations exhibited delayed fertilization. The optimal embryo rescue medium consisted of MS basal medium supplemented with 2,4-D or IAA (2.0 mg/L), 6-BA (0.5 mg/L), sucrose (30 g/L), and agar (7 g/L), with 40.0% of the rescue rate of immature embryos. The proliferation medium comprised MS basal medium supplemented with 6-BA (1.0 mg/L), sucrose (30 g/L), and agar (7 g/L), with 30.5 of the average of new buds. The rooting medium consisted of WPM basal medium supplemented with NAA (0.5 mg/L), sucrose (20 g/L), and agar (7 g/L), with 25.5 of the average of roots.

The female parent genotypes significantly affect the time when young fruits stop growing and drop, as well as the survival time of immature embryos in distant hybridization of Rosaceae stone fruit trees. The optimal periods for immature embryo rescue, when apricot, plumcot, and peach are used as female parents, are 12-18, 6-15, and 12-30 days after pollination, respectively. Among these, combinations using ‘Longwangmao’, ‘Fengweimeigui’, and ‘Zhongyoutao 4’ as female parents show relatively higher success rates in embryo rescue. Plant growth regulators such as 2,4-D, IAA, 6-BA, and NAA serve as critical additives during embryo rescue.