SPECTRAL BEHAVIOUR AND SPECTRAL SEPARABILITY OF ERODED LANDS USING MULTI-SENSOR DATA

A sound knowledge of the spectral behaviour of any feature or phenomenon helps to establish its spectral response pattern, which ultimately allows it to be detected and delineated using spectral measurements made by multispectral sensors aboard different platforms. The spectral behaviour of eroded lands and associated features was studied in part of the Bijapur District of Karnataka State using multispectral measurements made by the Landsat-multispectral scanner system (MSS) and thematic mapper (TM), and SPOT-HRV multispectral linear array (MLA) sensors under near-identical illumination and atmospheric conditions. The spectral separability of different categories of eroded lands was also studied using scattergrams and divergence analysis. © 1997 John Wiley & Sons, Ltd.     

马兜铃酸诱导小鼠淋巴瘤细胞tk基因突变的研究

马兜铃酸广泛存在于中草药和中成药中,该化合物已被证实可导致人类肿瘤。研究通过体外小鼠淋巴瘤细胞致突变试验来检测马兜铃酸(AA)的致突变率和药剂剂量的相关性,对试验具体所采用的96孔板法进行了详细的论述,并进而希望能够建立可以用于各种中草药遗传毒性检测的方法。经过试验证实了小鼠淋巴瘤细胞tk基因突变试验方法可以有效地检测马兜铃酸的细胞毒性和致突变性。并且随着AA剂量的增加,L5178Y细胞的相对存活率和悬浮生长率均明显降低。表明AA对L5178Y细胞具有明显的细胞毒性,并可以诱导tk基因的突变。     

施肥对尾叶桉MLA无性系幼林生物量及养分含量的影响

对建立在广东开平的尾叶桉MLA6年生无性系施肥试验林进行了生物量和养分的测定与分析,结果表明:尾叶桉MLA无性系幼林早期施肥促进了无性系的生长,也促进了生物量的增加。生长最佳的施肥处理N75P200K50,其6年生的生物量最大,地上生物量和树干生物量分别为65 95、54 94t·hm-2,分别是不施肥处理的2 37和2 36倍,分别是最大施肥量处理N75P300K75的1 65倍和1 67倍。通过胸径和树高与生物量建立的回归方程,可预测尾叶桉MLA无性系单株或林分生物量。叶片的N、P、K含量较高,施肥促进了尾叶桉无性系对营养元素的吸收和积累。     

Investigating nicotinic acetylcholine receptor expression in neonicotinoid resistant Myzus persicae FRC

The peach–potato aphid Myzus persicae is a pest of many commercial crops due to its polyphagous nature of feeding and has a well-documented history of acquiring resistance to insecticides. In 2009 a strain (M. persicae FRC) emerged in southern France with a point mutation (R81T) at the nicotinic acetylcholine receptor (nAChR), the target site for neonicotinoids such as imidacloprid. This point mutation was associated with the loss of the high affinity imidacloprid binding site (pM Kd), with the single remaining binding site (low nM Kd) highly overexpressed compared to laboratory controls (Bass et al., 2011 [1]). Here we report that after 2 years of continuous selection in the glass house environment with neonicotinoids, the total level of IMD-sensitive nAChRs (low nM Kd) in M. persicae FRC is now comparable to laboratory controls (pM and low nM Kd). Interestingly, despite this large reduction in IMD-sensitive nAChRs, this was not associated with any significant alteration in NNIC-lethality. Additionally, sustained absence of neonicotinoid-selection did not alter nAChR protein levels. We suggest that alterations in nAChR protein expression level described in the original characterisation of the field-isolated M. persicae FRC is unlikely to have been a direct consequence of the R81T mutation. Rather, we speculate that nAChR expression in aphids is likely influenced by as yet unknown conditions in the natural field environment that are absent in the laboratory setting.     

几种丛生竹叶性状随冠层高度的垂直变化规律

[目的]了解几种丛生竹叶的平均叶面积(MLA)、比叶面积(SLA)和叶干物质含量(LDMC)沿冠层高度的垂直变化规律。[方法]对福建农林大学百竹园内12种丛生竹不同冠层高度叶片MLA、SLA和LDMC进行调查,分析丛生竹不同冠层MLA、SLA和LDMC的垂直空间结构与差异。[结果]不同丛生竹的上、中、下冠层MLA与LDMC变化较小,SLA变化较大,MLA与LDMC均以唐竹最高(上、中、下冠层MLA均值分别为26.0、33.7、27.4 cm~2;LDMC分别为766.0、814.8、792.4 m~2/kg),LDMC以大黄苦竹最低(上、中、下冠层分别为528.4、548.5、479.0 mg/g);SLA均以高节竹最高(上、中、下冠层分别为629.0、284.9、440.7 m~2/kg);同竹种不同冠层间MLA差异不显著(P0.05);除白哺鸡竹外,其他11种竹种3个冠层间的SLA差异不显著(P0.05)。[结论]光照、水分资源及养分在冠层不同高度的分配,共同导致MLA、SLA和LDMC沿冠层垂直方向发生变化。     

施肥对尾叶桉无性系MLA生长影响的研究

在雷州林业局两个试验点进行了尾叶桉无性系ＭＬＡ施肥试验,林龄３８个月生的结果表明：处理⑥（Ｐ３００ｇ／株＋Ｋ３００ｇ／株＋１５０ｇ／株）的平均蓄积生长量为２９．２４ｍ＾３／ｈｍ＾２．ａ,比处理⑦（常规施肥,滤泥５０００ｇ／株＋Ｐ２５０ｇ／株＋Ｋ１５０ｇ／株）的平均蓄积生长量２６．２６ｍ＾２／ｈｍ＾２．ａ大１１;３％,比ｃｋ（不施肥）的平均蓄积生长量６．３９ｍ＾３／ｈｍ＾２．ａ大３５７．５９％,比总