蝗虫中黄酮含量的测定及最佳提取工艺

通过单因素及正交试验探讨不同品种蝗虫体内黄酮类化合物的最佳提取工艺,结果表明,在65°C下,以90%甲醇回流提取2 h,蝗虫中黄酮类化合物的得率最高,中华稻蝗中黄酮的含量高达20.15 m g/gDW。     

厄尔尼诺、拉尼娜事件及太阳活动对河北省夏蝗大发生的影响分析

利用灾变规律的关键时方法分析了厄尔尼诺(El Nino)、拉尼娜(La Nina)事件和太阳活动与河北省沿海型蝗区和淀洼型蝗区夏蝗大发生的关系。结果发现,El Nino、La Nina灾异事件不会促使河北省两类生态类型区夏蝗大发生,El Nino和La Nina事件对飞蝗大发生的影响主要是导致蝗区的天气气候产生异常。太阳活动对河北省两种生态类型区夏蝗大发生的影响也不明显,但在太阳黑子数峰值年时两种生态类型区夏蝗发生的情况存在差异。     

Medium‐ and short‐term available organic matter,microbial biomass,and enzyme activities in soils under Pinus sylvestris L. and Robinia pseudoacacia L. in a sandy soil in NE Saxony,Germany

Total, mobile, and easily available C and N fractions, microbial biomass, and enzyme activities in a sandy soil under pine (Pinus sylvestris L.) and black locust (Robinia pseudoacacia L.) stands were investigated in a field study near Riesa, NE Germany. Samples of the organic layers (Oi and Oe‐Oa) and the mineral soil (0–5, 5–10, 10–20, and 10–30 cm) were taken in fall 1999 and analyzed for their contents of organic C and total N, hot‐water‐extractable organic C and N (HWC and HWN), KCl‐extractable organic C and N (C_org(KCl) and N_org(KCl)), NH ‐N and NO ‐N, microbial‐biomass C and N, and activities of β‐glucosidase and L‐asparaginase. With exception of the HWC, all investigated C and N pools showed a clear response to tilling, which was most pronounced in the Oi horizon. Compared to soils under pine, those under black locust had higher contents of medium‐ and short‐term available C (HWC, C_org(KCl)) and N (HWN, N_org(KCl)), mineral N (NH ‐N, NO ‐N), microbial‐biomass C and N, and enzyme activities in the uppermost horizons of the soil. The strong depth gradient found for all studied parameters was most pronounced in soils under black locust. Microbial‐biomass C and N and enzyme activities were closely related to the amounts of readily mineralizable organic C (HWC and C_org(KCl)). However, the presented results implicate a faster C and N turnover in the top‐soil layers under black locust caused by higher N‐input rates by symbiotic N₂ fixation.     

PEG预处理对刺槐种子抗盐性的影响

刺槐(Robinia pseudoacacia Linn.)种子经过不同浓度PEG6 000水溶液浸种24h,然后观察种子在不同梯度NaCl胁迫下发芽.结果表明:10%PEG预处理下种子的发芽率、发芽势、发芽指数以及活力指数等指标最好;对照种子随着NaCl胁迫的加强各指标逐渐下降;20%PEG预处理种子的各指标变化无规律.不同预处理种子的表现说明水分胁迫与NaCl胁迫存在着一定的共性机理,但也有差异.     

杨树、刺槐混交及缺钾情况下对矿物钾的利用

本文通过沙培盆栽试验研究了１年生杨树、刺槐及两者混植对矿物Ｋ的利用，并采用封闭循环系统对树木生长过程中不同形态的变化进行了严格的数量化研究，同时研究了缺Ｋ胁迫下对矿物Ｋ的利用及对Ｎ，Ｐ，Ｋ积累的影响．结果表明：杨树、刺槐都可不同程度吸收矿物Ｋ，两者混交后利用矿物Ｋ的量有很大提高；缺Ｋ胁迫可提高植物吸收矿物Ｋ的量；缺Ｋ主要抑制根系生长，对地上部分影响较小；Ｋ元素对Ｎ的影响较大，对Ｐ的影响较小．     

IPM - Biological and integrated management of desert locust

Locusts have caused periodic disasters in the recorded history of humankind. Up to now, locust disaster is still the biggest threat to the world's agricultural production. The desert locust Schistocerca gregaria is one of the most harmful locusts, which has caused massive food crises, economic losses, and ecological disasters. The desert locust is a migratory insect pest that occurs year-round in the tropic and subtropical regions. Under the wind and seasonal alternation, it moves and flies in the African continent and West Asia. Desert locust damages the stems and leaves of more than 300 plants, including Gramineae, Tribulus terrestris, and Euphorbiaceae. Locusts cause devastating disasters to local plants, especially field crops, and significantly threaten food security. To date, voluminous research has been conducted regarding the ecology and management of desert locusts. This review represents an effort to summarize the basic information on the biology and ecology, distribution, damage, and economic impact of desert locusts, examine the recent developments in integrated locust management, and make recommendations for future research.     

乾隆年间伊犁蝗灾与政府应对

乾隆年间,蝗灾是伊犁农业开发中的主要自然灾害之一。清朝廷对蝗灾十分重视,从祈神禳灾、组织灭蝗、赈济减赔、外地调粮等途径积极应对。乾隆三十一年伊犁蝗灾事件与伊犁将军明瑞"来京陛见"存在内在关联。     

刺槐薪炭林特性的研究

发展薪炭林是尽快解决农村能源有效的途径之一,1983年经对凌源、建平刺槐薪炭林特性的测试表明:刺槐在半干旱地区的阳坡半阳坡薄土层山地生长较快,8年生进入材积速生期,水平根系发达,根幅3×12米~1,产柴量;朝南沟谷地高于半阴半阳坡地;造林后封山育林明显高于不封山育林;采用短周期平茬高于其它采柴方式。刺槐萌芽力强,12年生树平茬后平均每株发萌条9.6根,薪柴含水率较低(湿柴含水29％);易燃,湿柴就可做燃料,热值高于杨、柳树。     

刺槐生长量的灰色预测

通过对刺槐树高、胸径连年生长量的灰色预测ＧＭ（１，１） 模型的建立，提出长武王东试区刺槐人工林应采取早期利用，以培育小径材为目标的经营原则，以提高刺槐林的经济效益。一般最经济的采伐树龄为１４－１８。     

四倍体刺槐大小孢子发育时期与花器形态的相关性

本研究通过观察四倍体刺槐花器,得出相应的花蕾外部形态、大小、颜色和花序中不同序位花蕾发育时期与大小孢子细胞学发育时期密切相关。因此根据花器形态特征可判断大、小孢子发育细胞学的时期,从而为四倍体刺槐花器离体培养接种外植体的选择提供依据。