Biochemical and histological alterations of cellular metabolism from jerboa (Jaculus orientalis) by 2,4-dichlorophenoxyacetic acid: Effects on d-3-hydroxybutyrate dehydrogenase

2,4-Dichlorophenoxyacetic acid (2,4D) is one of the widely used herbicide of the phenoxy family with possible startling number of adverse effects on species other than the weeds which is designed to kill. The effects of 2,4D were investigated in jerboa (Jaculus orientalis), a wild animal of subdesert highlands. The jerboas have been daily treated intraperitonally with 2,4D 3 mg/kg body weight for 4 weeks. Plasmatic markers, and antioxidants defences systems were assessed and histological alterations were evaluated. The in vivo and in vitro effects of 2,4D on the mitochondrial d-3-hydroxybutyrate dehydrogenase (BDH) were also determined. Our results showed a strong decrease of triglycerides level and HDL cholesterol and an increase in GOT level and LDL cholesterol. The microscopic evaluation showed that 2,4D induced necrosis of seminiferous tubules cells in testis, hyperplasia of hepatocytes in liver and presence of multinucleated giant cells in brain. The results show also an inhibitory effect on BDH in terms of activity and kinetic parameters. All of these results show that 2,4D induces toxicity which affects energy metabolism, morphological perturbation and oxidative stress.     

Chemical cotton stalk destruction for maintenance of host-free periods for the control of overwintering boll weevil in tropical and subtropical climates

In the Lower Rio Grande Valley (LRGV) of Texas, cotton regrows and produces fruit from undestroyed stalks throughout the winter, and in spring weevils from such locations become a serious threat. The success of the boll weevil eradication program, which was reintroduced in the LRGV in 2005, will be dependent on thorough stalk destruction following harvest. However, adverse weather conditions and conservation tillage often impede immediate and complete stalk destruction using typical tool implements, and alternative stalk control methods are needed. This study provides an examination of the efficacy for cotton stalk destruction of different herbicides (thifensulfuron-methyl + tribenuron-methyl, dicamba-diolamine, 2,4-D-dimethylammonium, flumioxazin, 2,4-DB-dimethylammonium and carfentrazone-ethyl) and their rates, spray volumes and application timings on shredded or standing cotton stalks after stripper or picker harvest. None of the tested herbicides, except 2,4-D-dimethylammonium, stopped post-harvest cotton regrowth and fruiting. 2,4-D-dimethylammonium sprayed once (0 or 7 days) after cotton was harvested at 1 lb AE acre(-1) (1.12 kg ha(-1)), in a spray volume of 10 gal water acre(-1) (93.5 L ha(-1)) with 5 mL L(-1) surfactant, was highly effective in stalk destruction (72-90%). The best results were achieved when the herbicide was applied immediately after the cotton was shredded, followed by standing stripper-harvested and standing picker-harvested cotton. 2,4-D-dimethylammonium applied twice, 0 and 14 (or 21) days after cotton harvest, was 100% effective in killing stalks, regardless of whether they were shredded or standing, or whether harvest was by stripper or picker. These findings showed that 2,4-D-dimethylammonium cotton stalk destruction eliminated food and reproductive opportunities for managing overwintering boll weevils [Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae)].     

植物生长调节剂2，4-D 对两种绿藻生长的影响

测定了植物生长调节剂2，4-D(2，4-Dichlorophenoxyacetic acid)在不同浓度作用下对两种绿藻 --蛋白核小球藻和斜生栅藻增殖和叶绿素含量的影响。结果表明，0． 25 mg/L 和0． 50 mg/L 的2，4-D 分别是 促进小球藻和栅藻生长的最佳浓度；在0． 50 mg/L 的2，4-D 作用下小球藻和栅藻的叶绿素含量最高。高浓度 的2，4-D(＞4． 0 mg/L)对两种藻类的生长有毒性作用。     

Adsorption and degradation of 2,4-dichlorophenoxyacetic acid in spiked soil with Fe0 nanoparticles supported by biochar

This work studies the adsorption and degradation of 2,4-dichlorophenoxyacetic (2,4-D) in spiked soil with nanoscale Fe⁰ particles (nFe⁰) and biochar derived from maize straw. When biochar concentration was high, the adsorption capacity of soil was enhanced. Furthermore, 2,4-D degraded completely at loading rates of 0.33 and 0.17 g/L nFe⁰ plus biochar (initial 2,4-D concentration of 10 mg/g) within 40 h, according to equilibrium data. Additionally, the theoretical concentration of chloridion was approximately 84%. Further analysis indicated that the effect of nFe⁰ on 2,4-D degradation was weaker in soil columns than that in soil slurry. By contrast, 2,4-D degradation is positively influenced by biochar application, which prevented the aggregation and corrosion of Fe nanoparticles. Although the enhanced capacity for 2,4-D adsorption on the soil decelerated dechlorination rate, long-term nFe⁰ activity was generated. After 72 h, the efficiency of 2,4-D degradation was approximately 53.2% in the soil columns with biochar support.     

松香酸酯用于中性施胶的研究

合成了４种松香酯用于中性施胶。探讨了松香酯结构与施胶性能的关系,研究了施胶条件对香酯施胶效能的影响。松香酯在中,碱性条件下表现了优良的施胶效率。     

Influence of surface charge on viscosity behavior of cellulose microcrystal suspension

Microcrystalline cellulose with minimal surface charge was prepared from softwood kraft pulp via hydrolysis by 4N hydrochloric acid instead of sulfuric acid. To this material, sulfate ester groups as surface charge were introduced by treating with 55% (w/w) sulfuric acid. A treatment at 60°C for 2h gave nearly the same level of surface charge as that of the H₂SO₄ -hydrolyzed microcrystal. The number of sulfate groups were controlled by changing the H₂SO₄ treatment conditions. Although the microscopic size and shape of the microcrystalline particles were the same irrespective of the preparation method, the introduction of surface charge drastically reduced the viscosity and removed its time dependence. These changes in viscosity behavior are considered to result from charge-induced dispersion of loose aggregates existing in the initial charge-free microcrystals prepared by HCl hydrolysis.Part of this report was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998     

玉米幼苗对芘污染土壤微生物活性及多样性的影响

通过盆栽土培试验研究了玉米幼苗生长期间对芘污染土壤微生物活性及多样性的影响。结果表明,玉米加快了土壤中芘的降解,提高了芘在土壤中的降解速率。试验期间,根际土中可提取态芘含量显著低于非根际土,根际土微生物生物量碳、微生物熵、多酚氧化酶和脱氢酶活性均高于非根际土,代谢熵低于非根际土。脂肪酸（FAME）分析结果表明,与非根际土相比,芘污染玉米根际土微生物群落结构发生了显著的变化,主要表现在真菌特征脂肪酸以及真菌/细菌的比值显著升高,细菌和GN^-细菌特征脂肪酸显著降低,且这种效应随着培养时间的推移在P〈0.01水平显著。根际土和非根际土中丛枝菌根真菌、GN^＋细菌和放线菌特征脂肪酸差异随着培养时间的延长逐渐加大,45 d时其差异均在P〈0.05水平显著。     

18% 2，4 滴微乳剂防除薇甘菊技术的研究

在广东省深圳市薇甘菊为害严重的地区设置样地,用18%2,4-滴微乳剂不同浓度进行除治试验,结果表明:400～800倍液为有效浓度,1 000～1 200倍液为有效低浓度。不同生境样地防除试验结果表明:在山坡林地带可选用400～600倍液,在丘陵植被地带和果树周边地带可选用500～800倍液,在水塘、水库、水源周边地带以及菜地、花卉、药材和植物保护区周边地带可选用800倍液以下的有效低浓度。     

Antinociceptive and antiplasmodial activities of cassane furanoditerpenes from Caesalpinia volkensii H. root bark

The chloroform and ethyl acetate extract (100 mg/kg) of Caesalpinia volkensii H. exhibited significant (P ≤ 0.05) antinociceptive activities using hot plate and writhing tests in mice while the later showed antiplasmodial activity (IC₅₀ 0.23 ± 0.07 and 4.39 ± 2.49 μg/ml) against chloroquine sensitive (D6) and chloroquine-resistant (W2), respectively. Two new furanoditerpenes [rel. 1β,5α-dihydroxyvoucapane (1) and rel. 1β,6β-dihydroxyvoucapane; 19β-methyl ester (2)] together with seven known compounds [voucapane (3), voucapan-5-ol (4), deoxycaesaldekarin C (5), caesaldekarin C (6), 5-hydroxyvinhaticoic acid (7), triacontanyl-(E)-ferulate (8), triacontanyl-(E)-caffaete (9) and 30′-hydroxytriacontanyl-(E)-ferulate (10)] were isolated from the two extracts. The administration of 3, 4, 5 and 6 (100 mg/kg i.p) caused a significant (P ≤ 0.05) reduction in the number of writhing episodes induced by acetic acid and (P ≤ 0.01) increased pain latency threshold in hot-plate test compared to control. However, the pure compounds indicated relatively (P ≤ 0.05) low antiplasmodial activity. The phytochemical constituents from the root bark of C. volkensii had better analgesic properties than antimalarial properties, justifying the use of the plant root bark as a remedy for pain.     

脱落酸和2,4-表油菜素内酯对葡萄成熟过程中果实内源激素含量的影响

以酿酒葡萄"赤霞珠"和"烟73"为试材,研究了脱落酸(ABA)、2,4-表油菜素内酯(EBR)和BR生物合成抑制剂油菜素唑(Brz)处理对葡萄果实乙烯生成量、内源生长素(IAA)和赤酶素(GA3)含量的影响。结果表明:外源ABA和EBR处理促进了果实乙烯的释放,同时促进了果实着色,ABA和EBR处理后果实内源IAA和GA3含量略低于对照,但总体无显著差异。在不同浓度EBR处理中,以0.4mg/LEBR处理效果最显著。Brz处理抑制了乙烯的释放,推迟了果实着色,但对果实内源IAA和GA3含量没有显著影响。