New triterpenes from the leaves of Betula pendula and Betula ermanii

1991 ◽  
Vol 27 (1) ◽  
pp. 129-130 ◽  
Author(s):  
N. D. Pokhilo ◽  
V. A. Denisenko ◽  
N. I. Uvarova
TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 237-244 ◽  
Author(s):  
JONI LEHTO ◽  
RAIMO ALÉN

Untreated and hot water-treated birch (Betula pendula) sawdust were cooked by the oxygen-alkali method under the same cooking conditions (temperature = 170°C, liquor-to-wood ratio = 5 L/kg, and 19% sodium hydroxide charge on the ovendry sawdust). The pretreatment of feedstock clearly facilitated delignification. After a cooking time of 90 min, the kappa numbers were 47.6 for the untreated birch and 10.3 for the hot water-treated birch. Additionally, the amounts of hydroxy acids in black liquors based on the pretreated sawdust were higher (19.5-22.5g/L) than those in the untreated sawdust black liquors (14.8-15.5 g/L). In contrast, in the former case, the amounts of acetic acid were lower in the pretreated sawdust (13.3-14.8 g/L vs. 16.9-19.1 g/L) because the partial hydrolysis of the acetyl groups in xylan already took place during the hot water extraction of feedstock. The sulfur-free fractions in the pretreatment hydrolysates (mainly carbohydrates and acetic acid) and in black liquors (mainly lignin and aliphatic carboxylic acids) were considered as attractive novel byproducts of chemical pulping.


2019 ◽  
Vol 24 (2) ◽  
pp. 66-74
Author(s):  
Kristina Krupey ◽  
◽  
Katerina Obruch ◽  
A. Mihailichenko ◽  
◽  
...  

Author(s):  
Р. Х. Гиниятуллин ◽  
Алексей Юрьевич Кулагин

Представлены материалы по оценке относительного жизненного состояния и аккумуляции металлов различными надземными органами березы повислой (Betula pendula Roth.) в условиях технического загрязнения Стерлитамакского промышленного центра (СПЦ). Показано, что насаждения березы в СПЦ способны депонировать техногенные металлы в этих условиях.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 506d-506
Author(s):  
Robert R. Tripepi ◽  
Holly J. Schwager ◽  
Mary W. George ◽  
Joseph P. McCaffrey

Two insecticides, acephate or azadirachtin, were added to tissue culture media to determine their effectiveness in controlling onion thrips (Thrips tabaci Lindeman.) and to determine if these insecticides could damage the plant shoot cultures. To test for insecticide phytotoxicity, microshoots from European birch (Betula pendula), American elm (Ulmus americana), `Pink Arola' chrysanthemum (Dendranthema grandiflora), `America' rhododendron (Rhododendron catawbiense), `Golden Emblem' rose (Rosa hybrida), and `Gala' apple (Malus domestica) were placed in 130-ml baby food jars containing 25 ml of medium supplemented with 6.5, 13, or 26 mg/l Orthene® (contained acephate) or 0.55, 1.1, or 2.2 ml/l Azatin® (contained azadirachtin). Control jars lacked insecticide. To test for thrips control, 13 mg/l Orthene® or 0.55 ml/l Azatin® was added to Murashige and Skoog medium, and 10 thrips were placed on `Gala' apple microshoots in each jar. Jars were sealed with plastic wrap. In both studies, microshoot dry weight and heights were determined. In the second study, the total number of thrips per jar was also determined 3 weeks after inoculation. Microshoots on Orthene®-treated media lacked phytotoxicity symptoms, regardless of the concentration used. In contrast, Azatin® hindered plant growth, decreasing shoot height or dry weight by up to 85% depending on the species. Both insecticides prevented thrips populations from increasing, since less than 10 thrips were found in jars with insecticide-treated medium. Control jars, however, contained an average of almost 70 thrips per jar. This study demonstrated that both Orthene® and Azatin® were effective for eradicating thrips from plant tissue cultures, but Orthene® should probably be used because Azatin® was phytotoxic to all species tested.


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