黑绒金龟成虫虫体研磨物水悬液对其成虫的驱避作用

黑绒金龟[Serica orientalis(Motschulsky)]是一种重要的多食性林木食叶害虫,严重影响苹果、核桃和卫矛等经济和绿化树种的经济和生态效益。为研究黑绒金龟成虫虫体研磨物水悬液对其成虫的驱避作用,探索经济有效、环境友好的黑绒金龟行为控制技术,利用Y-型嗅觉仪测定了黑绒金龟对4种不同寄主植物[卫矛Euonymus alatus(Thunb.)Sieb.、苹果Malus pumila Mill.、箭杆杨Populus nigra var.thevestina(Dode)Bean、白梨Pyrus bretschneideri Rehd.]的趋性,以及不同寄主喷施其成虫虫体研磨物水悬液前后黑绒金龟的趋性差异。结果表明:雌、雄成虫对不同寄主的反应率,以及不同寄主对雌、雄成虫的诱引率和驱避率无显著差异(P0.05)。黑绒金龟对卫矛、苹果、箭杆杨和白梨均有极显著的正趋性(P0.01);对卫矛、苹果、白梨的趋性无显著差异(P0.05)。在4种寄主植物嫩枝叶上喷施黑绒金龟成虫虫体研磨物水悬液,以相应寄主嫩枝叶作为对照,比较对黑绒金龟的诱引率,发现黑绒金龟成虫虫体研磨物水悬液对黑绒金龟成虫有极显著的驱避作用(P0.01),黑绒金龟成虫的不反应率高于40%。研究结果可为害虫自身研磨物作为忌避剂应用于农、林业生产提供行为学依据。     

Indications for passive rather than active release of natural nitrification inhibitors in Brachiaria humidicola root exudates

Plants have the ability to suppress microbial nitrification process through secondary metabolites released from their root exudates or/and leaf litter. For decades, grasses were suggested to control nitrification process, and recently, Brachiaria humidicola accession 26159 (BH) as a tropical and subtropical grass has been shown to reduce nitrification rates under laboratory and soil conditions. In this study, experiments were conducted under controlled conditions in nutrient solution culture to investigate whether the reported release of natural nitrification inhibitors from root exudates of BH is an active or passive phenomenon. So different variables such as N-form (nitrate vs. ammonium), collecting medium (distilled water vs. 1 mM NH₄Cl) and collecting period (6 vs. 24 hrs) were included to study the hypothesis. Results showed when root exudates were collected in distilled water there was no nitrification inhibition activity for all ammonium and nitrate grown plants. However, when collection was done in a medium containing 1 mM NH₄Cl, root exudates showed significant nitrification inhibition activity similar to results obtained by Subbarao et al. The observed nitrification inhibition activity had a positive correlation to ammonium treatment particularly in collection medium, probably due to root cells damage induced by low pH and membrane depolarization under ammonium nutrition. This was more supported by application of shoot homogenates of NH₄⁺, NO₃^? or NH₄NO₃ grown plants that showed significant nitrification inhibition activity compared to distilled water and DMPP controls in a bioassay test, independent of N-form. Potassium concentrations in root exudates (as a result of potassium leakage) were found to increase in root washings of plants, which were grown with ammonium, particularly when root exudates were collected in 1 mM NH₄Cl solution. In addition, higher electric conductivity of root washings after collection of root exudates in ammonium containing medium (low pH) and also in nitrate containing medium which adjusted to pH 3 by applying H₂SO₄, strongly suggest that release of natural nitrification inhibitors from root exudates of B. humidicola may not be an active process, but instead it is rather a passive phenomenon by ammonium induced root physicochemical damages.     

Water immersion time reduces the preference of juvenile tropical spiny lobster Panulirus ornatus for pelleted dry feeds and fresh mussel

Development of a pelleted dry feed as an alternative to feeding fresh fishery by‐catch is an environmental priority for tropical spiny lobster aquaculture. Earlier studies have shown the lobster's acceptance of pelleted dry feed diminishes rapidly after immersion in water. In this work, we quantified the rate at which dry matter, total protein, soluble protein and individual and total free amino acids were lost from pieces of green‐lipped mussel Perna canaliculus, a commercially‐extruded Penaeus japonicus (kuruma) shrimp feed (KSF) and four laboratory‐made, fishmeal‐based, pelleted feeds upon immersion for up to 7.5 h. The laboratory‐made feeds contained homogenates of either green‐lipped mussel, polychaete (Marphysa sanguinea), prawn (Metapenaeus bennettae) or squid (Sepioteuthis spp.). After being immersed in water for 0, 2.5 or 5 h, these same feeds were offered as a paired choice with KSF in two preference feeding studies with juvenile Panulirus ornatus lobsters. The loobster's preference for fresh mussel always exceeded that of KSF, irrespective of immersion time. Regression of the proportional intake of test feeds against the relative leach rate of KSF identified soluble protein, glycine and taurine as the principal leachate components having the highest positive correlations with the lobster's feeding preference.     

不同浓度化学刺激物对多棘海盘车摄食行为及呼吸代谢的影响

实验室条件下,研究了3种贝类(太平洋牡蛎、紫贻贝、菲律宾蛤仔)不同浓度组织匀浆液及5种单一L型氨基酸(甘氨酸、谷氨酸、酪氨酸、天冬氨酸、赖氨酸)等化学刺激物对多棘海盘车(Asterias amurensis)摄食行为及呼吸代谢的影响。将多棘海盘车对刺激物的行为反应分为正趋向、负趋向和无反应3类,趋向反应由简单到复杂分为4种反应类型,通过测定耗氧率来表示呼吸代谢水平。结果显示,3种贝类组织匀浆液和5种氨基酸(浓度范围10 10~10 4mol/L,酪氨酸除外)均引起多棘海盘车的正趋向反应,且多棘海盘车产生反应的数量比例随刺激物浓度的升高而增加,反应类型也由简单逐渐趋于复杂。同种氨基酸在低浓度下引起多棘海盘车正趋向反应,但超过一定浓度(10 3~10 2mol/L)后会引起负趋向反应(实验浓度范围内谷氨酸组未出现)。不同种类刺激物对多棘海盘车摄食行为反应的影响不同,谷氨酸、甘氨酸以及菲律宾蛤仔组织匀浆液对多棘海盘车诱引效果最好。多棘海盘车的耗氧率随刺激物浓度的增加而逐渐升高。在贝类组织匀浆液中多棘海盘车的耗氧率均高于对照组;甘氨酸、谷氨酸、天冬氨酸各处理组中,只有在较高浓度下耗氧率才显著高于对照组,酪氨酸各组之间无显著差异。研究旨在为贝类底播增养殖和人工鱼礁区敌害生物的防除提供参考,同时为多棘海盘车觅食行为机制的研究提供数据支持。     

茶鲜叶匀浆悬浮发酵体系工艺放大指标的研究

为实现悬浮发酵红茶工业生产,对影响发酵体系工艺放大指标－容量传质系数（ＫＬａ）的因素及ＫＬａ对红茶品质形成的影响进行了初步研究,结果表明,ＫＬａ受发酵体系中搅拌速率、温度、通气量、装液量的影响;添加某有机物可明显提高发酵体系的ＫＬａ;随ＫＬａ的增大,发酵液中茶黄素类（ＴＦｓ）含量提高。