Abstract:In order to understand the survival status and regeneration mechanism of Pseudotsuga sinensis population, the community structure and spatial distribution pattern in Weining County Nature Reserve for P. sinensis of Guizhou Province were studied. The results showed that the diameter class structure of the population was a typical single-peak type, with more middle-aged individuals and fewer young and old individuals. The dynamic indexes (V_pi=13.49%, V'_pi=0.05%) of population structure showed a growth type, But the growth rate gradually decreased, and the sensitivity to external interference was higher. The survival curve of population tends to Deevey-II type, with the life expectancy decreased monotonously. The mortality rate showed a "V" type with two death peaks, the first appeared in I age class and the second in IX age class. Most of the sample plots showed cluster distribution, while Q2 and Q7 plots showed uniform distribution. The spatial distribution pattern changed from cluster distribution to uniform distribution along the age. Therefore, the main factor of endangered population of P. sinensis was the failure of young individuals to replenish population in time, it was suggested to strengthen seedling tending and promote regeneration of P. sinensis population through moderate disturbance.

Abstract:In order to explore the energy distribution and energy balance closure of the tropical seasonal rainforest in Xishuangbanna, China, the energy flux characteristics and closure features in different seasons were analyzed by using the continuous monitoring results of the eddy covariance system and conventional meteorological instruments. The results showed that the annual net radiation, latent heat flux, sensible heat flux, soil heat flux and heat storage were 4 546.07, 2 453.24, 492.22, -10.47 and 45.93 MJ/m², respectively. It was suggested that soil was a heat source. The latent and sensible heat fluxes were accounted for 54.0% and 10.8% of the net radiation, respectively. The main form of energy dissipation was evapotranspiration. There was obvious diurnal variation and seasonal dynamics in radiation and energy, and the diurnal variation of each energy components almost showed a unimodal trend of high daytime and low nighttime. The overall albedo ranged from 0.10 to 0.12, with a little fluctuation, and the seasonal variation of the Bowen ratio was significant, fluctuating from 0 to 0.8 throughout the year. The annual closure of tropical seasonal rainforest was 0.67, which varied from 0.51 to 0.79 when the heat storage was not considered, and from 0.53 to 0.80 when the heat storage was taken into account. Therefore, the contribution of heat storage to energy closure was small in tropical seasonal rainforest with dense forest canopies, and neglecting heat storage was not the main cause for energy non-closure.

Abstract:In order to reveal the leaf energy investment strategy of subtropical forest trees at different successional stages and the correlations between leaf construction cost and mechanical resistance, the suits of leaf traits, including force to tear (F_t), force to punch (F_p), leaf mass per area (LMA), leaf lifespan (LLS), leaf construction cost per area (CC_area), leaf cuticle thickness (T_c), and leaf maximum photosynthesis per area (A_area), for 14 dominant woody species from subtropical forests at different successional stages were measured, and the correlations between leaf construction cost and mechanical resistance were analyzed. The results showed that the dominant species from late successional forest had higher CC_area, F_t and F_p, but lower A_area than those in early successional forest. In addition, CC_area was positively correlated with both F_t and F_p. Moreover, the structural traits, such as T_c and LMA, were positively correlated with CC_area and mechanical resistance. Therefore, it was illustrated the coordination between CC_area and mechanical resistance, along with the changes in structural traits might be responsible (at least partially) for this shift of leaf energy investment strategy for trees occurred at different successional subtropical forests.

Abstract:To reveal the distribution law of lianas on tree trunk, the difference of Trachelospermum divaricatum with aerial root climbing strategy in different directions on the surface of Liquidambar formosana and Pinus massoniana was analyzed in a coniferous and broadleaf mixed forest in Jigong Mountain. The results showed that the distribution of T. divaricatum on the trunk of L. formosana and P. massoniana varied with the height of the tree. At basal diameter (5 cm height) of L. formosana, the number of T. divaricatum (6.6 ind./tree) attached in the northwest was significantly higher than that in the northeast (4.6 ind./tree) and southeast (4.3 ind./tree). At the breast diameter (130 cm height), the number of T. divaricatum growing in the southwest and southeast was significantly higher than that in the northwest. At the height of basal and breast diameter of L. formosana, the mortality of T. divaricatum in the south is significantly lower than that in the north. At the height of basal diameter of P. massoniana, the mortality of T. divaricatum was the highest (35.1%) in the northwest, thus lead to the least number of T. divaricatum (4.6 ind./tree). At the height of breast diameter of P. massoniana, the number of T. divaricatum distributed in the southeast was greater than the other directions. In addition, T. divaricatum mortality in the south was greater than that in the north. Therefore, there are significant differences in the distribution of T. divaricatum in different directions of climbing trees, which varied with height and diameter at breast height, indicating that the distribution pattern of liana was regulated by both microenvironment of the trunk and physiological feature of liana.

Abstract:In order to strengthen conservation of Machilus chinensis, the oldest species in Macao, the phenology of M. chinensis and M. velutina, the dominant species in the community, was monitored, the species composition, structure and species diversity of the community were studied by using sample plot method. The results showed that February to March was the peak growth period of new leaves of M. chinensis, the flowering period was from mid to late March,and the fruit period last from April to June. The peak period of new leaves of M. velutina was from April to May, the flowering period was from October to December, and the fruiting period was from December to March of the following year. There were 104 vascular species recorded in the plot of 2 000 m², belonging to 82 genera and 48 families. The flora of seed plants of the community was dominated by Tropical distribution type, accounting for 87.01% of the total flora. Although there was only one tall ancient tree M. chinensis in arbor layer, its importance value of 18.97% ranked the fourth among all tree species. And Machilus chinensis (seedlings with average height below 20 cm) ranked second with an important value of 37.06% in the shrub layer. Machilus velutina was the dominant tree species in arbor and shrub layers. The species abundance index was arbor layer>shrub layer>herb layer>liana; the evenness index was liana>herb layer>arbor layer> shrub layer. The Shannon-Wiener and Simpson indexes of herb layer were the highest, and those of shrub layer were the lowest. So, the community belongs to the subtropical evergreen broad forest, the species composition is relatively rich, the growth of ancient tree Machilus chinensis is normal, but the population is unstable, protection should be strengthened.

Abstract:In order to reveal the effects of global warming and changes in precipitation pattern on the below- ground ecological processes of forest ecosystems in the mid-subtropical regions of China, two-factor test of soil warming and isolating precipitation on Cunninghamia lanceolata was conducted at the National Field Station of Forest Ecosystems and Global Change in Sanming, Fujian Province. The results showed that compared with control (CT), the total fine root biomass of C. lanceolata saplings treated with warming (ambient+5℃, W), precipitation exclusion (ambient -50%, P) and W+P (WP) were significantly reduced by 35.7%, 51.7%, and 59.1%, respectively; the total fine root biomass treated with P and WP was significantly reduced by 24.9% and 36.4% compared with W treatment. W, P and WP increased specific root length (SRL) of 0-1 mm fine roots, while the specific root area (SRA) of 0-1 and 1-2 mm fine root had no significant changes. Compared with the CT, W had no effect on fine root N content, C/N and δ¹⁵N; P increased fine root N content and decreased fine root C/N; WP increased fine root N content, δ¹⁵N, and decreased fine root C/N. Therefore, adjusting the morphological characteristics of surface fine roots might not be the main strategy for C. lanceolata saplings under the dual environmental stress of global warming and precipitation reduction in the future. Compared with the increase of temperature, the precipitation reduction might be the main environmental factor affecting the fine root biomass and surface chemical element distribution of C. lanceolata saplings.

Abstract:In order to understand the effects of arbuscular mycorrhizal fungi (AMF) and addition different forms of nitrogen on the growth and nutrient uptake of Chinese fir (Cunninghamia lanceolata), the seedlings at 1-year-old were inoculated AMF (Glomus mosseae, Gm) and treated with different forms of nitrogen (NH₄⁺-N and NO₃^--N), the changes in nutrient elements and growth status were studied. The results showed that AMF increased significantly the seedling height, biomass and the uptake of N, P, K, Ca, Mg, Fe and Na, and the promotion effect of AMF on trace elements of Fe and Na was generally stronger than that of macro elements of K and Ca. Compared with the addition of NO₃^--N, the positive effect of AMF on biomass, C, N, Ca, Mg and Mn contents were more significant with the NH₄⁺-N addition. Moreover, the increased magnitude was stronger in leaves than that in root and stem. Therefore, it was suggested that the inoculation of AMF promoted the growth and nutrient uptake of Chinese fir seedlings. Additionally, the positive effects of AMF on growth and nutrient uptake treated with NH₄⁺-N were more prominent than that with NO₃^--N.

Abstract:In order to research the correlation between the endogenous auxin and defoliation of sugarcane, the contents of abscisic acid (ABA), ABA-glucosyl ester (ABA-GE), 1-aminocyclopropanecarboxylic acid (ACC), jasmonic acid (JA) and related derivatives jasmonic acid-valine (JA-val) in leaf sheath bases at different positions were determined at different mature stages. The results showed that the change trends of ABA and JA-val contents in LZ02-169 with maturity were consistent with that of shedding rate, while the ACC content in +8 leaf sheath base of LZ02-169 and defoliation rate was opposite. The contents of ABA, ABA-GE and JA-val in +8 leaf sheath base of LZ02-169 at late mature stage were significantly higher than those of 'GT47'. Therefore, the increase of ABA content might accelerate the abscission of sugarcane leaves at late mature stage, and ethylene derived from ACC and JA-Val also promoted the abscission of sugarcane leaves.

Abstract:In order to understand the flora characteristics of vascular plants in Longyandong Forest Farm, Guangzhou, Guangdong Province, the species composition, flora characteristics and endangered grade of vascular plants were investigated and analyzed by route survey. The results showed that there were 783 species, belonging to 473 genera and 151 families in the forest farm, including 11 dominant families in ferns, such as Lindsaeaceae, Adiantaceae, Dryopteridaceae, and 62 dominant families in spermatophytes, such as Convolvulaceae, Menisper- maceae, Caesalpiniaceae and Vitaceae. Compared with the areal types, the areal types at species level were more extensive than those at genera level with large tropical and subtropical components. Superior topographic features and unique subtropical humid climate interpenetrate and interweave, forming a lot of endemic to China species in the forest. There were also 12 key protected plants, eg. Alsophila spinulosa and Aquilaria sinensis. Especially A. spinulosa was in a vulnerable state. There were 681 resource species in the forest farm, which could be divided into four types, such as medicinal, edible, ornamental and industrial raw material species, and the medicinal species had the largest number covered 71.14% of the forest farm. Therefore, it was suggested to develop and utilize the resource plants and strengthen the protection of rare and endangered plants in the forest farm.

Abstract:Paris fargesii Franch. var. macrosepala H. X. Yin & W. X. Rao & L. Zhao, a new variety of Paris L. is reported in Hunan, China. It is different from P. fargesii Franch. var. fargesii by its outer tepals extremely broad, 6.5-11.0 cm long, 2.5-4.0 cm wide. The ratio of length of leaf to calyx is usually less than 2.0 (mean of 1.91), and the ratio of width of leaf to calyx is generally less than 3.0 (mean of 2.86). Inner tepals are shorter, 2.0-5.3 cm, often spread above the outer tepals. The free portion of connective is flat, with visible cracks, and the apical view looks like a butterfly or double kidney.

Abstract:The subspecies Lecanora subimmersa subsp. asiatica Zahlbr. was treated as one subspecies Aspicilia subimmersa (Fée) Hue subsp. asiatica (Zahlbr.) J. C. Wei, or listed as a synonym of L. subimmersa (Fée) Vain. subsp. subimmersa by previous researchers. The concept of that subspecies is confusing. The specimens of L. subimmersa subsp. asiatica Zahlbr. were studied in morphological, anatomical and chemical details. The morphological characteristics and secondary metabolites of this subspecies are consistent with those of L. oreinoides (Körb.) Hertel & Rambold. Therefore, L. subimmersa subsp. asiatica should be regarded a synonym for L. oreinoides. A detailed description of L. oreinoides, and morphological photos are provided in this paper.

Abstract:The lichen genus Xanthomendoza S. Y. Kondr. & Kärnefelt is reported as new record from China, with the species Xanthomendoza ulophyllodes (Räsänen) Søchting, Kärnefelt & S.Y. Kondr. In addition, Xanthoria calcicola Oxner, belonging to genus Xanthoria is also reported as new record from China. The internal transcribed spacer (ITS) region of Xanthomendoza ulophyllodes was sequenced to access in the phylogenetic tree, the differences among related taxa were discussed. The descriptions of two species are given with ecological distribution, and photographs are provided.

Abstract:To clarify the changes in volatile components of Dendrobium officinale, D. hercoglossum and their hybrid strains (14L-3, 14L-6, 14L-7 and 14L-9), their flowers were detected by static headspace combined with gas chromatography-mass spectrometry (GC-MS) technology. The results showed that there were 81 volatile components detected, including olefins, ketones, aldehydes, and alkanes. Among them, there are 23 compounds in D. officinale, 12 in D. hercoglossum, 21 in 14L-3, 33 in14L-6, 23 in 14L-7, and 35 in 14L-9. The main component in D. officinale flower was α-pinene, and that in D. hercoglossum was 2-pentadecanone. α-Pinene was the main component common in the four hybrids. The parents and hybrids contain hexanal. The hybrids 14L-3, 14L-6, and 14L-9 had high similarity with the female parent D. officinale in the order of 14L-3>14L-6>14L-9, they are quite different from the male parent D. hercoglossum. 14L-7 has the most balanced similarity with the parents. Therefore, these would provide guidance for breeding of Dendrobium.

Abstract:In order to understand the aroma substances of Nymphaea, the volatile components in flowers of 62 cultivars were studied by using Gas chromatography-mass spectrometry (GC-MS). The results showed that there were 72 volatile components detected from flowers, in which alkenes (26 types), alkanes (11 types), and alcohols (9 types) are the top 3, and there were 53 aromatic components, accounting for 73.60%. Fifty-six volatile components were detected from 40 cultivars of tropical waterlily, including 39 aromatic components, while 37 volatile components from 22 cultivars of hardy waterlily, including 27 aromatic components. The main aroma substances were benzyl acetate, cis-ocimene, benzyl alcohol, farnesene, myrcene, limonene, benzaldehyde, α-isoterpinene, α-pinene, cinnamyl alcohol, β-butanol, etc. According to volatile components and aromatic components of Nymphaea, 62 cultivars could be divided into 3 and 4 groups by using intergroup cosine connection method, respectively. Therefore, these would provide basic information for development and utilization of aroma substances of Nymphaea and the studies on co-evolution of Nymphaea with pollinators.

Abstract:The tropical rain forest (TRF) in Yunnan is similar to the rain forest of tropical Asia in floristic composition, forest profile, physiognomy and species richness, and is a particular type of the latter. It occurs at the northern margin of tropical Asia and is affected not only by the seasonal dryness of the monsoon climate, but also by the low temperature found at the relatively higher latitude and altitude. The flora of the TRF of Yunnan consists mainly of tropical floristic elements, which contribute more than 90% at the generic level and more than 80% at the specific level to its total flora. The dominant geographical elements are the tropical Asian distribution, which contributes about 40% of the genera and 70% of the species. Most of the dominant families, in terms of both numbers of species and tree importance values, are also similar to the Indo-Malesian rain forests. The formations of the TRF show clear floristic divergences between southwestern, southern and southeastern Yunnan because of the different floristic origins and evolutionary histories of these regions, although they are similar in ecological and physiognomic features. The TRF of Yunnan is maintained by the southwestern Asian monsoon. Uplift of the Himalayas triggered and strengthened the southwestern Asian monsoon climate, which created local wet habitats in tropical areas of Yunnan, and the tropical rain forest occurred locally. Based on the geological history and the palaeobotanical research in tropical Yunnan and adjacent regions, we suggest that a much drier climate prevailed in the later Tertiary or Quaternary periods, because there are drought-tolerant deciduous trees in the TRF and deciduous forests in the same areas as the TRF. The present TRF in Yunnan is an ecotone between tropical lowland and montane forests, and controlled mainly by local habitat factors.

Abstract:The natural resources of 17 species in genus Miscanthus were reviewed from the aspects of taxonomy, genetics, breeding and physiology, the current situation of resource utilization were summarized, and the application prospect and industrial value were further prospected. In addition, it was pointed out that the research depth and application degree of the taxa in Miscanthus were extremely unbalanced, as the development and utilization of the endemic groups suitable for extreme environment was not enough. In order to comprehensively promote the development and utilization of Miscanthus resources and assist the promotion of new varieties, it was proposed to strengthen the research and development of endemic germplasm resources within the genus, so as to realize much broader application prospects than now.

Abstract:Subgenus Ficus belongs to Moraceae, which is an important resource of fruit and herbal medicine. Ficus subgenus is widely planted in tropical and subtropical areas. It has outstanding economic value because of abundant bioactive compounds and multiple health benefits. Prenylated flavonoids are the characteristic bioactive compounds of Ficus subgenus, including 37 isoflavones, 2 flavanones, 7 flavones, and 1 chalcone. Numerous biological activities have been reported for these prenylated flavonoids, such as menopause relief, bone protection, anti-inflammation, anti-oxidation, cancer prevention and anti-bacteria activities. The updated information regarding the prenylated flavonoids in Ficus subgenus was summarized, and also their chemical structures and biological activities. The information is helpful for the development and utilization of this subgenus.