不同条件下水杨酸对蚕豆气孔开度的影响

水杨酸（ＳＡ）被认为是一种在植物体内广泛存在的新的植物生长调节物质［１］,能够调节植物体内的许多生理过程,如产热、开花、性别分化、离子吸收、乙烯的合成、气孔开闭等等,并与植物的抗病性密切相关,可能作为植物的防御信号［２］．有报道,蚕豆表皮条细胞对ＳＡ高度敏感,１０－６ｍｏｌＬ－１ＳＡ就可使气孔关闭［３］,ＳＡ能降低菜豆和鸭趾草的蒸腾［４］,但也有ＳＡ逆转ＡＢＡ诱导的气孔关闭的报道［５］．因此,有必要对ＳＡ和气孔运动的关系进行研究,以探索ＳＡ是否作为一种信号,参与对气孔运动的调节,进而影响其他生理…     

Stress response to nanoplastics with different charges in Brassica napus L. during seed germination and seedling growth stages

● Higher concentrations of PS, PS-NH₂ and PS-SO₃H inhibited seed germination. ● PS, PS-NH₂ and PS-SO₃H influenced seedling growth in a dose-dependent manner. ● PS, PS-NH₂ and PS-SO₃H reduced essential nutrients uptake and plant quality. ● PS, PS-NH₂ and PS-SO₃H increased antioxidant enzyme activities and MDA content. ● Nanoplastic toxicity was related to surface charges. Nanoplastic pollution has become a significant problem in farmland systems worldwide. However, research on the effects of nanoplastics (NPs) with different charges on field crops is still limited. In our study, NPs with different charges, including unmodified polystyrene nanoplastics (PS), positively charged polystyrene nanoplastics (PS-NH₂), and negatively charged polystyrene nanoplastics (PS-SO₃H), were investigated for their impacts on seed germination and seedling growth of rape. The results showed that seed water uptake (after 12 h), seed germination, seed vigour, and relative root elongation were all significantly reduced under exposure to NPs (200 mg/L). Similarly, remarkable decreases in plant biomass (root weight, shoot weight), growth (root length, plant height), photosynthesis ability (chlorophyll a, chlorophyll b, carotenoids), essential nutrient uptake (Fe, Mn, Zn, Cu), and plant quality (soluble protein, soluble sugar, crude fibre content) of rape seedlings were also observed after exposure to NPs. Among the three kinds of NPs, PS-NH₂ showed stronger effects. Moreover, superoxide dismutase, peroxidase, and catalase activities of rape seedlings were changed, and the content of malondialdehyde was significantly increased under exposure to NPs. Furthermore, positively charged PS-NH₂ showed stronger effects on the phenotype, physiology, biochemistry, nutrient uptake, and plant quality of rape. Notably, a comprehensive toxicity evaluation revealed that PS-NH₂ had the strongest toxicity to rape. The present study provides important implications for the interaction and risk assessment of NPs and crops in soil-plant systems.     

Biologically active antimicrobial and antioxidant substances in the Helianthus annuus L. bee pollen

The objective of this study was to measure the content of flavonoids, polyphenols, and carotenoids in the Helianthus annuus L. bee pollen. It was also to evaluate the ability of the dried, frozen, and freeze-dried extracts of sunflower (H. annuus) pollen, its scavenged free radicals and reducing action. Another aim of this study was to investigate the antimicrobial in vitro action of the H. annuus pollen extracts against the Gram-positive and Gram-negative bacteria and fungi. All pollen extracts showed medium antiradical activity and reductive ability. The most effective was the freeze-dried extract in both evaluation systems. The evaluation of the protective effects of DNA using a biosensor showed an opposite trending—frozen ? dried ? freeze-dried pollen. For the evaluation of antiradical activity, the DPPH method was used, and reductive ability was assessed by means of phosphomolybdic complex formation. The comparison of the polyphenols content shows higher values in freeze-dried bee pollen than in the dried and frozen pollen. The highest content of flavonoids was found in the frozen samples and the most carotenoids were present in the dried samples. In our study, the best antibacterial effects of the dried sunflower bee pollen extracts were found against Paenibacillus larvae, Pseudomonas aeruginosa, and Enterococcus raffinosus. The best inhibitory properties of the frozen sunflower bee pollen extracts were found against Escherichia coli, Pseudomonas aeruginosa, and Paenibacillus larvae. Very good inhibitory effects of freeze-dried sunflower bee pollen were found against Paenibacillus larvae, Brochotrix thermosphacta, and Enterococcus raffinosus. The best antifungal activity of the sunflower bee pollen was found in the frozen bee pollen extracts against Aspergillus ochraceus and freeze-dried bee pollen extracts against Aspergillus niger.     

西葫芦对土壤持久性有机氯化物污染的指示性研究

西葫芦(Cucurbita pepo L.)对土壤中持久性有机氯化物的超强吸收能力已被证实,意味其具有指示区域土壤持久性有机氯化物污染状况的潜能。本研究采用农田小区试验,考察了西葫芦不同组织器官(根、过渡茎、茎、叶和果实)在6个生长期对有机氯化物的累积吸收行为;采用同位素稀释高分辨气相色谱-高分辨质谱法,分析了种植土壤及西葫芦各组织器官中的21种有机氯农药(OCPs)和18种多氯联苯(PCBs)。结果表明,西葫芦可将根吸收的OCPs和PCBs传递到过渡茎和茎。不同生长期采集的西葫芦根、过渡茎和茎中的OCPs和PCBs浓度基本稳定,无明显生物稀释效应,且此3个组织器官中OCPs和PCBs的分布模式与土壤中的分布模式基本一致。因此,可以用西葫芦根和茎中持久性有机氯化物的浓度指示土壤中持久性有机氯化物的污染水平,根和茎的采样时间可以不受西葫芦生长期的限制。     

阿维菌素对意大利蜜蜂(Apis mellifera L.)的毒性影响

通过单次饲喂高浓度阿维菌素药液以及连续饲喂亚致死浓度阿维菌素药液进行意大利蜜蜂的经口染毒,从而探讨阿维菌素对意大利蜜蜂的急性及慢性毒性影响。结果表明,阿维菌素对意大利蜜蜂急性经口毒性48 h半数致死剂量(48 h-LD50)为0.00700μg a.i.·蜂-1,慢性经口毒性240 h每日半数致死剂量(240 h-LDD50)为0.000308μg a.i.·蜂-1·天-1。在亚致死效应方面,0.0233 mg a.i.·L-1和0.0467 mg a.i.·L-1处理组在168 h后摄食量出现明显的减少,说明阿维菌素中毒已经严重影响意大利蜜蜂的觅食和摄食能力。同时,由于摄食量的下降以及阿维菌素的毒性作用,造成了0.0467 mg a.i.·L-1处理组意大利蜜蜂体重的大幅度下降,试验前后的体重变化率达到-54.84%。意大利蜜蜂爬行能力的测定结果显示,各处理组的爬行通过率均低于对照组,特别是0.0117 mg a.i.·L-1处理组、0.0233 mg a.i.·L-1处理组和0.0467 mg a.i.·L-1处理组(P0.05)。综上所述,阿维菌素对意大利蜜蜂的急性经口毒性为高毒,较高剂量染毒会引起意大利蜜蜂的直接死亡;此外,长期接触较低浓度的阿维菌素,一方面会损害意大利蜜蜂的运动能力,如爬行、飞行能力的减弱;另一方面意大利蜜蜂生理方面也会遭到威胁,表现为摄食量下降、体重减轻,甚至死亡。因此,在施用该农药时应尽量避开蜜蜂栖息地,同时避免在蜜源植株花期时施用。     

Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution.     

Are Bavarian Forests (southern Germany) at risk from ground-level ozone? Assessment using exposure and flux based ozone indices

Exposure and flux-based indices of O₃ risk were compared, at 19 forest locations across Bavaria in southern Germany from 2002 to 2005; leaf symptoms on mature beech trees found at these locations were also examined for O₃ injury. O₃ flux modelling was performed using continuously recorded O₃ concentrations in combination with meteorological and soil moisture data collected from Level II forest sites. O₃ measurements at nearby rural open-field sites proved appropriate as surrogates in cases where O₃ data were lacking at forest sites (with altitude-dependent average differences of about 10% between O₃ concentrations). Operational thresholds of biomass loss for both O₃ indices were exceeded at the majority of the forest locations, suggesting similar risk under long-term average climate conditions. However, exposure-based indices estimated higher O₃ risk during dry years as compared to the flux-based approach. In comparison, minor O₃-like leaf injury symptoms were detected only at a few of the forest sites investigated. Relationships between flux-based risk thresholds and tree response need to be established for mature forest stands for validation of predicted growth reductions under the prevailing O₃ regimes.     

荠菜叶挥发性成分分析

采用水蒸气蒸馏法对荠菜叶挥发油进行了提取。通过毛细管气相色谱—质谱联用法分离并鉴定了其化学成分,用气相色谱面积归一化法测定了各成分的相对百分含量,共分离确定了其中12种化合物,所鉴定化合物的含量占全油的65.62%,主要化学成分为：L-胍基琥珀酰亚胺（21.28%）、植醇（18%）、植酮（9.6%）、油酸（4.71%）、棕榈酸（3.97%）等。     

苜蓿培养细胞抗羟脯氨酸变异体的筛选和特性分析

以返地卫星搭载的苜蓿（ＭｅｄｉｃａｇｏｓａｔｉｖａＬ．）种子为实验材料,取其无菌苗下胚轴切段诱导愈伤组织,该愈伤组织经正筛选法,获得抗脯氨酸类似物Ｌ羟脯氨酸（Ｈｙｐ）的变异细胞系（Ｈｙｐｒ）．Ｈｙｐｒ脱离选择压力３ｍｏ后,对Ｈｙｐ的抗性仍比对照强,ＦＷ细胞内游离脯氨酸ｗ＝０．７２ｍｇ／ｇ,是ＣＫ的３．４３倍,同时还具有对ＮａＣｌ和ＰＥＧ的交叉抗性．和ＣＫ相比,Ｈｙｐｒ愈伤组织可溶性蛋白质ＳＤＳＰＡＧＥ图谱出现两条新多肽（Ｍｒ≈５６×１０３、３２×１０３）;其过氧化物酶同工酶谱中酶活性明显高于对照,并出现１条新带,酯酶同工酶酶谱中亦出现３条新带．这些特性分析表明,该变异细胞系对Ｈｙｐ的抗性是稳定的．     

流化床生物反应器培养青蒿毛状根生产青蒿素

利用自制的流化床生物反应器进行青蒿毛状根多层培养生产青蒿素．对毛状根在生物反应器生长过程的形态特征进行观察,并在合适的工艺条件下,经２０ｄ分批培养获得生物量干重２１．３ｇ／Ｌ,青蒿素产量３４９．８ｍｇ／Ｌ,并对培养过程中底物消耗的动力学进行了研究．