具有化感作用的植物能增强花生对黄曲霉毒素的抗性（英文）

研究三裂叶蟛蜞菊、香根草、香茅对黄曲霉的化感作用。结果表明,三种植物的水提液均能显著抑制黄曲霉的生长。在培养黄曲霉的培养基中加入上述三种植物的水提液后,培养基上黄曲霉的菌落数显著减少,平均菌落直径变小。利用这三种植物的水提液浸泡被黄曲霉感染的花生种子,其发芽率显著高于清水对照处理;显示这三种植物的水提液能够缓解黄曲霉素对花生种子发芽的抑制作用。在没有黄曲霉侵染的条件下,虽然这三种植物的水提液会降低正在发芽的花生种子某些水解酶和保护酶的活性;但在黄曲霉侵染后,这三种植物水提液浸泡过的花生种子水解酶和保护酶的活性却显著高于对照处理,导致处理种子具有更高的呼吸速率、种子活力和发芽率。在对照土壤里,受黄曲霉侵染的种子长出的花生植株长势很差。分别将三种化感植物剪碎、加入土壤中混匀,平衡一段时间;在这些土壤上种植受黄曲霉侵染的种子长出的花生发现能够有效降低黄曲霉素对花生生长的抑制作用。与对照相比,处理土壤上生长的受黄曲霉侵染的花生植株具有更高的根系活力、叶绿素含量、净光合速率、硝酸还原酶和谷氨酰胺合成酶活性,因而具有更高的株高、叶片氮素含量和干物量。     

以广东高州普通野生稻为供体亲本的水稻单片段代换系构建

以栽培稻品种粤香占为受体亲本,利用杂交、回交和微卫星标记辅助选择相结合的方法,构建了以高州普通野生稻为供体亲本的水稻单片段代换系群体。该群体由20个编号的9个单片段代换系构成。这9个单片段代换系分别分布在水稻的第1、2、3、10和11染色体上,代换片段长度为8.1～23.8cM,总长度为152.7cM,平均长度为17.0cM,代换片段对水稻基因组的覆盖总长度为136.1cM,覆盖率为7.5%。构建以高州普通野生稻为供体亲本的水稻单片段代换系,为发掘和利用高州普通野生稻的有利基因提供了理想的试验材料,为进一步开展高州普通野生稻的遗传研究提供了一条新途径。     

天然产物防治果蔬采后病害研究进展

果蔬采后病害的防治正朝着安全、环保的方向发展,各种生物防治方法成为研究的热点,天然产物用于控制果蔬采后病害的研究也受到了越来越多的关注。本文综述了风味化合物、精油、乙酸、茉莉酸类化合物、芥子油甙、蜂胶、植物提取物、壳聚糖、醋酸瓜类萎蔫醇等天然产物在果蔬采后病害防治中的研究、开发与应用,为未来的商业化开发提供新的思路。     

辣椒碱对斜纹夜蛾细胞增殖及凋亡的影响

采用3-(4,5-二甲基-2-噻唑)-2,5-二苯基溴化四唑(MTT)检测法、荧光显微镜细胞形态观察法和流式细胞仪(flow cytometry,FCM)技术,研究了辣椒碱对离体培养斜纹夜蛾Spodopt-era litura(SL)细胞增殖及凋亡的影响。结果表明:辣椒碱对SL细胞24 h的IC50值为46.89μg/mL,与鱼藤酮差异不显著。40μg/mL辣椒碱处理SL细胞24h后,细胞形态明显不规则,呈现出凋亡的典型症状。10、20和40μg/mL辣椒碱处理SL细胞48h后,细胞早期凋亡率分别为13.56%、18.61%和3.81%,而晚期凋亡和坏死率分别为23.78%、34.28%和61.72%。辣椒碱处理细胞48h后,细胞周期变化明显,细胞生长阻滞于G2/M期。表明辣椒碱对斜纹夜蛾细胞具有良好的抑制作用,能致细胞凋亡并有一定的浓度依赖性。     

苦瓜叶提取物对黄曲条跳甲成虫的拒食作用

本文研究了苦瓜Momordica charantia叶片提取物对黄曲条跳甲Phyllotreta striolata成虫的拒食活性,结果表明,用4000μg/ml苦瓜叶片乙醇提取物对黄曲条跳甲成虫的取食有明显的抑制作用。用石油醚、乙酸乙酯、正丁醇和水依次对苦瓜叶片乙醇提取物进行萃取,在4种萃取物中,乙酸乙酯萃取物对黄曲条跳甲成虫的拒食作用最强。用2000μg/ml和4000μg/ml的苦瓜叶乙酸乙酯萃取物处理甘蓝叶片48h后,在选择性试验中对黄曲条跳甲成虫的拒食率分别为41.42%和66.27%;在非选择性试验中的拒食率分别为30.90%和59.62%。     

生长调节剂PrimoMAXX对狗牙根草坪草生长的影响

[目的]研究生长调节剂PrimoMAXX对狗牙根草坪草生长的影响,为华南地区PrimoMAXX在狗牙根草坪上的应用提供依据。[方法]采用单因素随机区组试验设计,研究不同浓度的PrimoMAXX对狗牙根草坪草自然生长高度、叶色及地上部鲜重的影响。[结果]不同浓度的PrimoMAXX对狗牙根的生长高度有较好的抑制作用,且各浓度之间差异不显著;适量施用PrimoMAXX可以丰富草坪色彩;施药后35d狗牙根茎变粗。[结论]在华南地区狗牙根草坪上使用有效剂量为150～300g/hm2的PrimoMAXX较为适宜。     

Anti-Insect Activity of the Methanol Extracts of Fern and Gymnosperm

With environmental and food safety issues becoming one of the greatest concerns of the public, active plant compounds play more and more important roles in pest controlling. Fern to their particular status in plant taxology and co-evolution are of great significance for application as new pesticides due with insects. In this study, methanol extracts were distilled from wild fern and gymnosperm of 54 species of 22 families collected from Shiwandashan Mountain in Guangxi Zhuang Autonomous Region of China. Insecticidal activities of the methanol extracts were assayed on both adult house fly （Musca domestica） and mosquito （Aedes albopictus）. Significant insecticidal activities were exhibited in the methanol extracts of five species, Cupressusfunebris （leaves and stems）, Cycas acuminatissima （roots）, Keteleeria fortunei （leaves and stems）, Onychium japonicum （whole plant）, and Pinus taiwanensis var. Darning shanensis （leaves and stems）. Applications of the extracts of these plants resulted in higher than 50% mortalities in 4th instar larvae of A. albopictus at 24 h after treatment. The methanol extracts from 13 species possessed insecticidal activities against the adult of M. domestica at 48 h after treatment with higher than 90% mortalities. The extensive screening results showed that these fern and gymnosperm were highly potential to be botanical insecticides. The findings provide a feasible and valuable basis for further investigation.     

Analysis of Disequilibrium Hybridization in Hybrid and Backcross Progenies of Saccharum officinarum × Erianthus arundinaceus

Erianthus arundinaceus is an important, closely related genus of Saccharum officinarum L. It is therefore important to understand how the chromosomes are transmitted when it hybridizes with sugarcane. The hybrids and backcross progenies of S. officinarum and E. arundinaceus and their parents were used for Karyotype analysis and to study the law of chromosome transmission. The results showed that the somatic chromosome number of both of the E. arundinaceus Hainan92-105 and Hainan92-77 were 2n = 60 = 60sm, belonging to type 1 A, and the BC1 YC01-21 was 2n = 104 = 100m ＋ 4sm, belonging to type 2C. The other six tested clones belonged to type 2B. The both F1s YC96-66 and YC96-40 that originated from Badila （2n = 80 = 70m ＋ 10sm） with E. Arundinaceus were 2n = 70 = 68m ＋ 2sm, which suggests an n ＋ n transmission. The cross between YC96-66 （female parent） and CP84-1198 （male parent, 2n = 120 = 114m ＋ 6sm） also followed the same genetic law and the somatic chromosome number of their progeny, YC01-3 （2n = 105 = 95m ＋ 10sm）. The cross derived from YC96- 40 （female） and CP84-1198 （male）, YC01-21 had 2n = 104 = 100m ＋ 4sm chromosomes, following the same genetic law of n ＋ n. However, YC01-36 had 2n = 132 = 130m ＋ 2sm chromosomes, which suggests a 2n ＋ n chromosome transmission. It can be inferred that the inheritance of chromosomes was very complex in the BC1. The difference in chromosome number between clones was as high as 28. This could be explained by the 2n ＋ n transmission of chromosomes. In addition, as there was not be a regular number of haploids, this phenomenon is termed as disequilibrium hybridization.     

Sub-Lethal Effects of Fenvalerate on the Development,Fecundity, and Juvenile Hormone Esterase Activity of Diamondback Moth,Plutella xylostella （L.）

The toxicities of fenvalerate （20% EC） to the 3rd instar larvae of diamondback moth （DBM）, Plutella xylostella （L.）, reared on three host plants viz., radish, oilseed rape, and cabbage were tested. The LC50 values of fenvalerate to the 3rd instar larvae of DBM varied with host plants, however, there wasn＇t any significant difference among them （P〉 0.05）. Similarly, DBM fed on three host plants had same pupal weight, pupal period, pupation rate, adult emergence rate, female ratio, and fecundity. The activity of juvenile hormone esterase （JHE, EC 3.1.1.1） in the 3rd instar larvae of DMB did not significantly vary with host plants, either. These suggested that DBM had similar fitness on the three host plant species. When fed on the host plants pretreated with fenvalerate at the concentrations equivalent to LC20, LC50 and LC50, the pupation rate, pupal weight, adult emergence rate, female ratio, fecundity, and JHE activity of the tested insects were declined as compared with insects in control treatments fed on the same host plant species. Furthermore, the pupal period of the tested insects was extended after fenvalerate treatment. The decrease in JHE activity after fenvalerate treatment in the tested insects could partly explain the changes in the mentioned growth parameters. Whether the role of fenvalerate in the inhibition of JHE activity could serve as a new way to control DBM needs further investigation.