Degradation kinetics and safety evaluation of buprofezin residues in grape (Vitis vinifera L.) and three different soils of India

BACKGROUND: This work was undertaken to determine the preharvest interval (PHI) of buprofezin to minimize its residues in grapes and thereby ensure consumer safety and avoid possible non‐compliance in terms of residue violations in export markets. Furthermore, the residue dynamics in three grapevine soils of India was explored to assess its environmental safety. RESULTS: Residues dissipated following non‐linear two‐compartment first + first‐order kinetics. In grapes, the PHI was 31 days at both treatments (312.5 and 625 g a.i. ha^?1), with the residues below the maximum permissible intake even 1 h after foliar spraying. Random sampling of 5 kg comprising small bunchlets (8–10 berries) collected from a 1 ha area gave satisfactory homogeneity and representation of the population. A survey on the samples harvested after the PHI from supervised vineyards that received treatment at the recommended dose showed residues below the maximum residue limit (MRL) of 0.02 mg kg^?1 applicable for the European Union. In soil, the degradation rate was fastest in clay soil, followed by sandy loam and silty clay, with a half‐life within 16 days in all the soils. CONCLUSION: The recommendation of the PHI proved to be effective in minimizing buprofezin residues in grapes. Thus, this work is of high practical significance to the domestic and export grape industry of India to ensure safety compliance in respect of buprofezin residues, keeping in view the requirements of international trade. Copyright © 2008 Society of Chemical Industry     

Growth and gut morphology of diploid and triploid juvenile Atlantic cod (Gadus morhua)

The objective of this paper was to compare the growth and gut morphology of juvenile diploid and triploid Atlantic cod (Gadus morhua) reared under similar conditions. Individually tagged 36‐week‐old diploid (mean weight 49.3 ± 13.8 g) and triploid (mean weight 43.6 ± 11.2) juvenile cod were measured at intervals during a 29‐week growth trial. Data for weight, length, condition factor (K), hepato‐somatic index (HSI), gonado‐somatic index (GSI), Relative Gut Length (RGL) and pyloric caeca number were collected and results were analysed in relation to ploidy status, gender and family contribution. At the end of the experiment, only one family (M2xF3) had many representatives with a relatively even distribution of sexes and ploidies. Diploid females were significantly heavier and had higher K than triploid females in the M2xF3 family (body weight 371.2 ± 120.2 vs. 298.4 ± 100.7 g; K 1.1 ± 0.1 vs. 0.93 ± 0.1), but no differences were found between diploid and triploid males. In the other families (pooled data), no differences in body weight were found between the ploidy groups. In general, triploids had a shorter intestine (RGL) and fewer pyloric caeca than their diploid siblings regardless of gender suggesting possible impairments in nutrient utilization and growth.     

庆阳冬半年最低气温的变化特征分析

为了研究庆阳市冬半年最低气温变化特征,分析气候变化对农业生产的影响,根据庆阳有代表性的3个站的冬半年平均最低气温资料,使用统计检验方法,分析了1960年以来庆阳冬半年最低气温的时空变化规律及最低气温突变事实。结果表明：庆阳在55 年以来,冬半年最低气温在波动中呈上升趋势,以南部塬区最为显著。在资料分析期内,最低气温均发生显著突变,进入异常增暖时期。因此,庆阳各地的冬半年最低气温的波动升高,农耕期延长,热量资源增加,为当地的特色农业及农业产业结构调整带来新的发展空间,但由此带来的病虫害流行蔓延风险增大,应引起重视。     

重金属离子与消毒药物对澳洲龙纹斑幼鱼的急性毒性

为了获知重金属离子与消毒药物对澳洲龙纹斑幼鱼的急性毒性浓度,选用硫酸铜、硫酸锌、氯化镉、硝酸铅4种重金属化合物与二氧化氯、聚维酮碘、高锰酸钾、甲醛、食盐5种消毒药物,通过调配不同浓度,对澳洲龙纹斑幼鱼进行急性毒性试验,采用静水法测定9种消毒药物及重金属离子对澳洲龙纹斑幼鱼每隔24h的LC50(半数致死浓度)、LC100(绝对致死浓度)和SC(安全浓度)。结果表明,硫酸铜、硫酸锌、氯化镉、硝酸铅、二氧化氯、聚维酮碘、高锰酸钾、甲醛、食盐对澳洲龙纹斑幼鱼的安全质量浓度(SC)分别为0.122 3、0.571 3、0.020 0、0.461 2、5.030 0、0.532 4、0.958 9、6.960 0、1.584 0mg·L~(-1)。综合分析认为,4种重金属化合物与5种消毒药物对澳洲龙纹斑的急性毒性的大小顺序为:氯化镉硫酸铜硫酸锌聚维酮碘高锰酸钾硝酸铅食盐二氧化氯甲醛。     

低温胁迫对栎黄枯叶蛾越冬卵发育和存活的影响

【目的】明确低温胁迫对栎黄枯叶蛾(Trabala vishnou gigantina Yang)越冬卵发育和存活的影响,以便预测其发生范围并采取有效的防治措施。【方法】将栎黄枯叶蛾越冬卵在6个低温(-15,-20,-25,-30,-35和-40℃)条件下处理12,24和48h或在-30℃下处理不同时间(1,3,5,10,20,30,50d),每日观察卵的发育情况,统计卵的发育历期和存活率。【结果】低温胁迫强度和处理时间对栎黄枯叶蛾越冬卵的发育和存活有显著影响,随着温度的降低和处理时间的延长,越冬卵的发育历期延长,存活率降低。越冬卵在-35℃低温下分别处理12,24和48h后,其发育历期显著长于其他处理。当温度≤-30℃时,无论处理时间长短,越冬卵的存活率均大幅度下降。越冬卵处理12,24和48h的致死中温度分别为-33.45,-32.08和-30.69℃,-30℃下致死中时间为19.63d。【结论】栎黄枯叶蛾越冬卵的抗寒性较强,大部分可以安全越冬。     

基于云模型的黄河故道砀山酥梨气候适宜性分析

选取黄河故道砀山酥梨代表性产地砀山县为样点,利用梨树物候期长期定位观测资料和气象监测数据,基于云模型理论建立了光、温、水气候适宜度。采用加权综合法和几何平均法,确定不同物候期和年际气候适宜度。结果表明,日照适宜度可由左半云,气温与降水适宜度可由梯形云来刻画。综合气候适宜度与梨果实际单产、气候产量和单株产量的相关系数分别为0.4452(P0.05)、0.3734和0.5620(P0.01)。1961-2015年,砀山酥梨气候适宜度变化趋势不明显,但1961-1989年和1990-2010年分别为气候适宜度偏高与偏低时段,1987年为气候适宜度累计距平最大年份。研究期间,气温适宜度呈极显著增加趋势,每10a约增加0.0274。日照与降水适宜度无明显变化趋势,降水适宜度平均值比日照和气温适宜度低,且变异系数是日照和气温适宜度变异系数的4倍。各物候期气候适宜度未呈现趋势性变化,但萌芽期和花期的气候适宜度偏低,在0.50~0.53,且变异系数较大,在45.0~57.0。其它物候期气候适宜度和变异系数相对偏小。在气候变化背景下,气温升高对梨果生长有利,砀山酥梨生产中应加强萌芽-花期的管理,以增强梨树的气候适宜性。     

Quinoa (Chenopodium quinoa Willd.) protein hydrolysates with in vitro dipeptidyl peptidase IV (DPP-IV) inhibitory and antioxidant properties

The potential of quinoa to act as a source of dipeptidyl peptidase IV (DPP-IV) inhibitory and antioxidant peptides was studied. A quinoa protein isolate (QPI) with a purity of 40.73 ± 0.90% was prepared. The QPI was hydrolysed at 50 °C for 3 h with two enzyme preparations: papain (P) and a microbial papain-like enzyme (PL) to yield quinoa protein hydrolysates (QPHs). The hydrolysates were evaluated for their DPP-IV inhibitory and oxygen radical absorbance capacity (ORAC) activities. Protein hydrolysis was observed in the QPI control, possibly due to the activity of quinoa endogenous proteinases. The QPI control had significantly higher DPP-IV half maximal inhibitory concentrations (IC₅₀) and lower ORAC values than QPH-P and QPH-PL (P < 0.05). Both QPH-P and QPH-PL had similar DPP-IV IC₅₀ and ORAC values. QPH-P had a DPP-IV IC₅₀ value of 0.88 ± 0.05 mg mL⁻¹ and an ORAC activity of 501.60 ± 77.34 μmol Trolox equivalent (T.E.) g⁻¹. To our understanding, this is the first study demonstrating the in vitro DPP-IV inhibitory properties of quinoa protein hydrolysates. QPHs may have potential as functional ingredients with serum glucose lowering properties.     

外源生长素对半海水胁迫下玉米幼苗叶片衰老特性的影响

为了探讨在盐渍环境下外源生长素对植物生长的调节作用,以抗性玉米品种农大108为材料,研究了50%比例海水处理过程中吲哚乙酸(indole acetic acid,IAA)对玉米幼苗叶片衰老相关指标的影响。结果表明:随着处理时间的延长,叶片中的叶绿素含量以及叶绿素a/叶绿素b降低,类胡萝卜素含量升高,而可溶性蛋白含量、丙二醛含量和超氧物歧化酶活性先上升后下降,说明半海水胁迫可以加快叶片的衰老进程;补充使用不同浓度的吲哚乙酸后,丙二醛水平下降,其余指标保持在较高的水平上,其中0.5 mg/L的吲哚乙酸处理组的衰老指标变化最明显,说明适宜浓度的外源生长素可以延缓海水胁迫造成的植物叶片衰老。     

Behaviour of trifloxystrobin and tebuconazole on grapes under semi‐arid tropical climatic conditions

BACKGROUND: A mixture of trifloxystrobin and tebuconazole is excellent in controlling both powdery and downy mildew of grapes. The objective of the present work was to study the behaviour of trifloxystrobin and tebuconazole on grape berries and soil following treatment with Nativo 75 WG, a formulation containing both fungicides (trifloxystrobin 250 + tebuconazole 500 g kg^?1). This study was carried out for planned registration of this mixture for use on grapes in India. RESULTS: Initial residue deposits of trifloxystrobin and tebuconazole on grapes were below their maximum residue limit (MRL) of 0.5 and 2 mg kg^?1, respectively, when Nativo 75 WG was applied at the recommended dose of 175 g product ha^?1. The residues dissipated gradually to 0.02 and 0.05 mg kg^?1 by 30 days, and were below the quantifiable limit of 0.01 mg kg^?1 at the time of harvest (60 days after the last treatment). Trifloxystrobin and tebuconazole dissipated at a pre‐harvest interval (PHI) of 36 and 34 days, respectively, from the recommended treatment dose. The acid metabolite of trifloxystrobin, CGA 321 113, was not detected in grape berries at any point in time. Soil at harvest was free of any pesticide residues. CONCLUSION: Residue levels of both trifloxystrobin and tebuconazole were below MRLs when grapes were harvested 30 days after the last of four applications of 175 g product ha^?1 (trifloxystrobin 44 g AI ha^?1, tebuconazole 88 g AI ha^?1) under the semi‐arid tropical climatic conditions of India. Copyright © 2010 Society of Chemical Industry