The Effect of Low Irradiance on Leaf Nitrogen Allocation and Mesophyll Conductance to CO2 in Seedlings of Four Tree Species in Subtropical China

Low light intensity can lead to a decrease in photosynthetic capacity. However, could N-fixing species with higher leaf N contents mitigate the effects of low light? Here, we exposed seedlings of Dalbergia odorifera and Erythrophleum fordii (N-fixing trees), and Castanopsis hystrix and Betula alnoides (non-N-fixing trees) to three irradiance treatments (100%, 40%, and 10% sunlight) to investigate the effects of low irradiance on leaf structure, leaf N allocation strategy, and photosynthetic physiological parameters in the seedlings. Low irradiance decreased the leaf mass per unit area, leaf N content per unit area (Narea), maximum carboxylation rate (Vcmax), maximum electron transport rate (Jmax), light compensation point, and light saturation point, and increased the N allocation proportion of light-harvesting components in all species. The studied tree seedlings changed their leaf structures, leaf N allocation strategy, and photosynthetic physiological parameters to adapt to low-light environments. N-fixing plants had a higher photosynthesis rate, Narea, Vcmax, and Jmax than non-N-fixing species under low irradiance and had a greater advantage in maintaining their photosynthetic rate under low-radiation conditions, such as under an understory canopy, in a forest gap, or when mixed with other species.

NGHIÊN CỨU QUÁ TRÌNH TRÍCH LY POLYSACCHARIDES TỪ NẤM LIM XANH (GANODERMA LUCIDIUM)

Nấm Lim xanh (Ganoderma lucidium) thuộc họ nấm gỗ mọc trên thân của cây Lim xanh (Erythrophleum fordii) đã chết. Nấm Lim xanh được khẳng định là loại dược liệu có ích cho sức khỏe con người và được dùng làm thuốc từ lâu đời. Đa số các sản phẩm từ nấm Lim xanh thông dụng hiện nay trên thị trường Việt Nam chủ yếu là nấm quả thể khô hoặc tai nấm khô cắt lát, có rất ít sản phẩm chế biến tiện dụng. Trong nghiên cứu này nấm Lim xanh được nuôi cấy tại phòng nuôi cấy mô Khoa Công nghệ Sinh học và Công nghệ Thực phẩm, Trường Đại học Nông Lâm Thái Nguyên - Đại học Thái Nguyên. Nghiên cứu đã xác định điều kiện để trích ly các polysaccharide từ nấm Lim xanh nuôi cấy là: thời gian xử lý sóng siêu âm 4 phút, hàm lượng polysaccharide đạt 4,26 mg/g; nồng độ ethanol 80 %, hàm lượng polysaccharide đạt 4,81 mg/g; tỉ lệ nguyên liệu/dung môi là 1/20 (g/ml), hàm lượng polysaccharide đạt 4,98 mg/g; thời gian trích ly là 90 phút, hàm lượng polysaccharide đạt 5,32 mg/g; nhiệt độ 80 oC, hàm lượng polysaccharide đạt 5,83 mg/g.

Cassaine Diterpenoid Amide from Stem Bark of Erythrophleum fordii Suppresses Cytotoxic and Induces Apoptosis of Human Leukemia Cells

Cassaine diterpenoids amides from the stem bark of Vietnamese Erythrophleum fordii Oliver were screened for their cytotoxic activity against human cancer cells. The cell proliferation assay results showed that, among the active compounds, 3β-acetyl-nor-erythrophlamide (3AEP) exhibited the most potential cytotoxicity against human leukemia HL-60 and KG cells with IC50 values of 12.0 ± 1.2 and 18.1 ± 2.7 µM, respectively. Treatment of 3AEP resulted in the apoptosis of HL-60 cells via the activation of caspase 3, and poly (ADP-ribose) polymerase (PARP). Molecular docking in silico results showed that the 3AEP can bind to both the procaspase-3 allosteric site and the PARP-1 active site, with binding energies of −7.51 and −9.63 kcal/mol respectively. These results indicated that the stem bark of Vietnamese E. fordii and its cassaine diterpenoid amides may be useful in the apoptosis induction of human leukemia cancer cells.

A Comparative Evaluation of Three Stem Profile Equations for Three Precious Tree Species in Southern China

Accurately describing the stem curve of precious tree species and estimating the quantity of various types of wood and their volume in the tropics can provide technical support for reasonable bucking. This study utilized Erythrophleum fordii, Castanopsis hystrix and Tectona grandis as study objects. Forty replicates of each species were used for a total of 120 individual trees. Their tape equations were constructed using simple tape equations, segmented taper equations and variable form taper equations. Statistical indicators were utilized to determine the best taper equation for the three types of precious tree species. A number of methods were compared and analyzed, including the index of correlation, the residual sum of squares, the mean prediction error, the variance of prediction errors and the root mean square error. Finally, a preliminary quantitative analysis was conducted to determine the trends of these three types of tree species. The result shows that the precision of the three predictions developed for each species is high, and, in particular, the segmented taper equations with optimized algorithms is the best. The tendency of the three species to vary was shown to be the highest for T. grandis in the range of 0.0 to 0.8 for its relative height, followed by E. fordii, while the variation of C. hystrix was the smallest. However, in the range of 0.8 to 1.0 relative height, the variation of Castanopsis hystrix was the largest, and the variation of both E. fordii and T. grandis were almost the same. Therefore, the segmented taper equations with optimization algorithms was recommended to fit the three types of tree species in the tropics. These types of equations can be used to estimate the stumpage and timber quantity and as a guide reasonable bucking for these three species.

Restoration of forest and it’s influence on the lower layer of phytocenosis after selective logging in the central of Vietnam

Цель работы изучение воздействия подлеска и живого напочвенного покрова на возобновление наиболее ценных пород вечнозеленого широколиственного леса после выборочных рубок в лесах Центрального Вьетнама. Исследовательские работы проведены в 2017 г. на участках выборочных рубок лесной компании Чук А , в районе Хюнг Кхе, провинция Ха Тинь, на высотах 200300 м н. у. м. Изучали подрост четырех наиболее экономически ценных видов из 1-го яруса: Vatica tonkinensis, Madhuca pasquieri, Hopea pierrei, Erythrophleum fordiiна участках рубок 2005, 2008, 2010 и 2012 гг. в лесных типах IIIА2 и IIIА3. Интенсивность рубок 2530 по запасу. Густота подроста на участках рубок возрастает, по сравнению с контролем. Подрост Vatica tonkinensis отличается от других видов стабильностью численности на лесосеках разных лет. Численность Hopea pierrei возрастает с увеличением давности рубок, что свидетельствует о его теневыносливости. Светолюбивый подрост Erythrophleum fordii, напротив, имеет высокую густоту на лесосеке 5-летней давности. Густота Madhucapasquieri существенно не отличается от контроля. Встречаемость подроста также выше на участках рубок. Корреляционная связь густоты и встречаемости подроста в большинстве случаев очень высокая: r 0,950,99. Суммарная доля четырех пород в общем составе подроста увеличивается с возрастом рубки. На контроле этого не наблюдается. Количество подроста всех четырех видов снижается с увеличением его высоты. Мелкого (высотой до 0,5 м), как правило, несколько больше на местах рубок, по сравнению с контролем, независимо от вида, у самого крупного наблюдается обратная тенденция. В целом, на местах выборочных рубок 512-летней давности подрост наиболее ценных древесных видов отличается от контроля большей густотой, встречаемостью и долей в общем составе подроста. На участках рубок выявлено увеличение густоты подлеска и степени проективного покрытия живого напочвенного покрова. Однако не установлено значительного влияния усиления присутствия нижних ярусов растительности как на общую густоту подроста ценных древесных видов, так и на численность мелкого подроста. Богатая почва и благоприятный климат Центрального Вьетнама способствуют быстрому восстановлению ценных пород после выборочных рубок независимо от разрастания подлеска и живого напочвенного покрова. Purpose to study the effects of the shrubs andcover of field layer on the renewal of the most valuable species of evergreen broad-leaved forest after selective logging in the central of Vietnam. Research work was carried out in 2017 in the areas of selective logging of the Chuс A forest company, in the Huщng Khe district, Ha Tinh province, at altitudes of 200300 m. Four of the most economically valuable undergrowth species from the 1st layer were studied: Vatica tonkinensis, Madhuca pasquieri, Hopea pierrei, Erythrophleum fordii in the selective logging areas of 2005, 2008, 2010 and density of the undergrowth in the areas selective logging increases compared with the control. The undergrowth Vatica tonkinensis different from other kinds of population stable at logging sites of different years. Hopea pierrei number increases with prescription cuttings, which indicates its shade tolerance.The photophilous undergrowth Erythrophleum fordii, on the contrary, has a high density in the selective logging area in 5 years ago. The density of Madhuca pasquieri is not significantly different from the control. The occurrence of undergrowth is also higher in selective logging areas. The correlation between the density and occurrence of undergrowth in most cases is very high: r 0.950.99. The total share of the four species in the overall composition of the undergrowth increases with cutting age. On the control of this is not observed. The number of undergrowth of all four species decreases with increasing height. Small (up to 0.5 m high), as a rule, is slightly larger at the logging sites as compared with the control, regardless of species, the largest is observed the opposite tendency. In general, in the places of selective logging 512 years ago, the undergrowth of the most valuable tree species differs from the control in the greater density, occurrence and share in the total composition of the undergrowth. In areas of logging, an increase in the density of shrubs and the cover the soil surface was revealed. However, no significant effect of the increased presence of the lower layer of vegetation on both the total density of valuable undergrowth species and the number of small undergrowth has been established. The rich soil and favorable climate of Central Vietnam contribute to the rapid restoration of valuable species after selective logging, regardless of the growth of the shrubs and the cover the soil surface.