Plant growth inhibitors: Patchoulane-type sesquiterpenes from Cyperus rotundus L.

Two sesquiterpene ketones, cyperotundone and α-cyperone, were isolated from dried tubers of purple nutsedge ( Cyperus rotundus L.) as major constituents: ≈0.26% and 0.1% of dried tuber, respectively. These allelochemicals affect plant growth, but we consider that these terpenoids undergo modification when they are released into the rhizosphere from the donor plant. For the structure–activity relationship study, cyperotundone was oxidized with selenium dioxide in acetic acid to 4-patchoulene-2,3-dione and 4-patchoulene-2,3,6-trione. Subsequent hydrogenation of 4-patchoulene-2,3-dione and 4-patchoulene-2,3,6-trione gave hydroxylated derivatives, cyperotundon-2-ol and 3-hydroxy-4-patchoulene-2,6-dione, respectively. 4-Patchoulene-2,3-dione inhibited the hypocotyl growth of lettuce seedlings but promoted radicle elongation at 0.1−2 mg L⁻¹ concentration without chlorosis. Moreover, this radicle elongation recovered with the addition of galactose and was not antagonized by gibberellin A₃. The effect of 4-patchoulene-2,3,6-trione showed a similar chlorosis, caused by 3,6,9-sugetriol triketone, against lettuce seedlings. These ketones did not show the radicle elongation.     

不同日月龄兔感染RHDV后圆小囊的比较病理学观察

为探讨圆小囊在免体全身抗感染免疫中的功能作用，采用组织病理学及免疫组织化学方法，对比观察了2日龄、1月龄及2月龄实验免感染RHDV后圆小囊的病理变化，同时采用ELISA方法对实验兔的血清及肝、肾、脾中的RHDV含量进行了测定，重点对实验兔圆小囊黏膜上皮内淋巴细胞(IEL)进行了统计比较，结果显示：2月龄以内兔人工感染RHDV后，临症表现、剖检及组织病理学观察均未见异常。血清及RHDV的靶器官肝、脾、肾中均未检测出RHDV抗原。2月龄以上兔感染RHDV后，无论从临床症状，还是大体剖检，组织病理学观察，均出现了明显的病理学改变，而且感染后血清RHDV抗原检测呈阳性反应。圆小囊、肝、脾、肾等组织器官都呈现RHDV免疫组化强阳性反应。2月龄以内的乳兔及仔兔感染RHDV后，圆小囊虽未出现明显的形态结构改变，免疫组化染色也未见RHDV抗原阳性反应物，但IEL明显增多，2日龄兔IEL由1．2％增加到4．2％；1月龄兔的IEL由10．1％增加到26．1％。1月龄仔兔还表现出固有层中淋巴细胞明显增多。     

Effect of soil solarization on true potato (Solanum tuberosum L.) seed germination, seedling growth, weed population and tuber yield

Summary True potato seed of 17 progenies were evaluated during 2002-03 and 2003-04 crop seasons for 12 characters related to seed germination, seedling growth and weed population in nursery beds and tuber yield of transplanted seedlings under non-solarized field conditions. Solarization was found to have beneficial effect on seed germination, seedling growth and yield of transplanted seedlings. Total weeds and major annual weedCornopus didymus were reduced to a great extent due to solarization. However solarization had no effect onCyperus rotundus. Progenies also showed significant differences among themselves for the various characters studied. The progeny x solarization interaction was also significant for all the characters. Yield increase in present study shows that the approach involving raising of seedlings in solarized nursery beds and subsequent transfer of seedlings to non-solarized field would be cost-effective and profitable for raising true seed crop of potato.     

香附子为耕葵粉蚧的新寄主

2019年7月在河南农业大学许昌教学试验场夏玉米田发现耕葵粉蚧为害香附子, 这是该种昆虫在田间取食香附子的首次报道?本文简要描述了耕葵粉蚧在香附子上的取食特点, 为进一步研究其生态学特性及防治技术提供了重要基础?