杨梅根瘤Frankia菌对重金属的抗性

采用生长抑制分析法研究从杨梅根瘤分离的10个Frankia菌菌株对9种重金属元素的抗性。一般所有供试菌株对Hg^2 和Ag^ 敏感，大部分菌株对Pb^2 (5～10mmol／L)、Cr2O7^2-(5～10mmol／L)、AsO2^-(5～10mmol／L)不敏感，部分菌株对Cu^2 、Co^2 、Ni^2 和Cd^2 也不敏感(MICs≥O．5mmol／L，有的菌株达到5mmol／L)。菌株之间对各种重金属的抗性存在较大差异，其中菌株Mda21对所有供试重金属都敏感，而菌株Mpall几乎能抗所有供试重金属，且有几个菌株能同时抗多种重金属。低浓度铅能促进抗铅菌株的生长，而高浓度铅对其生长有一定的抑制；抗铅菌株在含铅的培养基中仍具有固氮酶活性，在一定浓度范围内，随铅离子浓度的升高，固氮酶活性有所增强。Frankia菌的抗铅机理可能是其具有结合或螯合铅离子作用，对其他重金属的抗性机制尚不清楚。     

杨梅的需钾特性及施钾对杨梅的增产效应

钾对杨梅产量和品质的影响仅次于微量元素硼。杨梅对N：P2O5：K2O的需要比例分别为1：0．5：2．69。浙江省杨梅主产区土壤（0-20cm）的全钾和速效钾含量分别为1．81-2．41g／kg和83-121mg/kg。施钾能显著提高杨梅产量和改善果实品质。株产50kg果实的杨梅树以施用1．0～1．5kg氯化钾并配施50g硼砂的效果较好，杨梅进行叶面施钾时以喷施0．5％KCl或0．5％磷酸二氢钾的效果较佳。     

果蝇对云南杨梅的危害及发生规律研究初报

通过对云南杨梅主产区的果蝇种类鉴定、栖息场所及危害发生规律调查,结果表明：危害云南杨梅果实的主要害虫为双翅目（Diptera）果蝇科（Drosopilidaes）果蝇属（Drosophila）果蝇.果蝇广泛分布于杨梅园及其周边多种生态环境,具有发酵物、潮湿阴凉的生态环境,是果蝇栖息的主要场所和主要虫源;成虫的日活动高峰期为清晨和黄昏;果蝇对杨梅发生危害时期较早,杨梅生长中后期,果实肉质生硬,味酸稍甜时即被果蝇取食危害,随着杨梅的不断成熟,危害加剧,且果蝇对不同杨梅品种的危害程度和空间分布存在显著差异.     

红壤退化地杨梅林土壤对养分补偿的响应

2016年在福建省长汀县河田镇车寮村杨梅园以东魁杨梅(Myrica rubra cv.DongKui)林为试验材料,在了解当地东魁杨梅的栽培情况及对林下土壤养分分析的基础上,开展复合肥、菌肥、磷肥、菌肥+磷肥4种土壤养分补偿试验,分析0~20、20~40 cm土层对不同土壤养分补偿方式的响应。结果表明:在pH值响应上,0~20、20~40 cm土层施用菌肥、磷肥均与对照差异显著,施用菌肥、菌肥+磷肥与对照差异较小。其中以施用磷肥的pH值最高(4.78),施用菌肥的pH值最低(4.39),其它处理的pH值均有小幅度提高。施菌肥可以明显提高土壤中有机质、全磷、速效氮、速效磷和速效钾的含量,0~20 cm土层有机质、全磷、速效氮、速效磷和速效钾含量分别比对照提高13.7%、19.0%、18.4%、572.1%、29.4%,20~40 cm土层分别比对照提高11.0%、23.5%、5.7%、465.3%、84.8%,在全磷、速效磷和速效钾中存在显著差异。施菌肥+磷肥可以提高土壤中全钾、速效氮、速效钾的含量,其中对提高全钾含量效果最明显,0~20、20~40 cm土层中速效氮含量分别提高17.3%、110.2%,速效钾含量分别提高63.5%、96.9%。通过主成分分析得出,0~20 cm土层以施菌肥的综合效果最显著,20~40 cm土层以施菌肥+磷肥的综合效果最显著。     

Optimization of triploidy induction in the blacklip abalone, Haliotis rubra (Leach, 1814), using 6-dimethylaminopurine

Optimal conditions of 6‐dimethylaminopurine (6‐DMAP) for triploidy induction in the blacklip abalone Haliotis rubra (Leach, 1814) were investigated, targeting inhibition of second polar body (PB2) formation. Two experiments were conducted at a water temperature of 17.5–18.5°C where factorial combination of (1) four dosages (DSs) of 100, 150, 200 and 250 μM 6‐DMAP, four starting times (STs) of 15, 20, 25 and 30 min post fertilization, and two treatment durations (TDs) of 20 and 30 min and (2) three DSs of 50, 100 and 150 μM 6‐DMAP, three STs of 15, 20 and 25 min post fertilization, and three TDs of 10, 20 and 30 min, were applied respectively. Day 3 larvae were sampled for triploidy and survival. Percent triploidy was verified using flow cytometry (FCM). Results show that optimal inductions that combine both high rates of triploidy and reasonable survival were those treatments commenced 15 or 20 min post fertilization and continued for 20 or 30 min, using 100 μM 6‐DMAP. These conditions induced rates of triploidy and relative survival of 80.5–93.3% and 36.5–40.2%, respectively, in the first experiment, and corresponding rates were 79.1–93.6% and 20.7–43.0% in the second experiment. High percent triploidy were also obtained in a number of treatments using 150 μM 6‐DMAP, but with overall survival rates generally lower than those using 100 μM 6‐DMAP.     

Effects of oxygen supersaturation and temperature on juvenile greenlip, Haliotis laevigata Donovan, and blacklip, Haliotis rubra Leach, abalone

Growth and survival of juvenile greenlip (39.03 (SD 3.80) mm (n=524)) and blacklip (31.92 (SD 4.19) mm (n=531) abalone were investigated at high dissolved oxygen levels (95–120% saturation) between 17 and 19°C. Abalone were fed the same artificial diet and each species was contained in groups of approximately 30 individuals within triplicate tanks for each of six treatments and were exposed to flow through water adjusted to give experimental conditions for up to 75 days. Blacklip abalone held at 16.9°C and 97% oxygen saturation grew in shell length significantly faster than all other treatments of blacklip abalone held at 19°C, and significantly faster than blacklip abalone maintained at 111% oxygen saturation and 17.5°C. Both temperature and oxygen saturation significantly affected the survival of this species. Blacklip abalone held at 19°C had significantly lower survival for both 96% oxygen saturation and 120% oxygen saturation, compared with blacklip abalone maintained at either 110% oxygen saturation and 19°C, or for any 17°C treatment. No significant differences were noted for greenlip abalone within the range tested in terms of growth rate, food consumption rate or survival, indicating that greenlip abalone tolerated these conditions better than did blacklip abalone.     

杨梅衰弱病根际土壤真菌的定量检测与分析

 杨梅衰弱病在杨梅主产区发生严重,但其成因尚未明确。为明确根际土壤真菌与衰弱病的相关性,本研究以来自仙居、临海和兰溪3个不同地区的健康植株和衰弱植株的根际土壤为材料,利用实时荧光定量PCR技术,对14种与连作障碍相关的土壤真菌进行了定量检测与分析。结果表明:杨梅根际真菌群体的含量比较丰富;被孢霉属(Mortierella spp.)和轮枝孢属(Verticillium spp.)在发病植株根际的含量均显著高于健康植株,与杨梅衰弱病呈正相关关系;青霉菌属(Penicillium spp.)在发病植株根际的含量显著低于健康植株,与杨梅衰弱病呈负相关关系。本研究建立了杨梅根际土壤真菌的快速检测体系,明确了健康株和衰弱株根际真菌菌群的差异,为杨梅衰弱病的研究和病害防控提供参考。     

安康市5种冷季型草坪草外观质量评价研究

对安康市5种冷季型草坪草的综合评价表明:高羊茅质地较粗糙,越夏性能良好,在安康市外观质量综合评价最高;多年生黑麦草质地稍好,越夏性能较差,但能很快恢复;紫羊茅、草地早熟禾、匍匐剪股颖质地好,越夏性能差,恢复较困难,外观质量综合评价较差.     

杨梅根瘤Frankia菌的分离和培养特性研究

从荸荠种杨梅根瘤中分离获得3个内生菌株,经显微镜检查、回接、固氮活性测定、革兰氏染色检测,证实这3个内生菌为3个Frankia sp.,分别命名为Mpc11、Mpc12、Mpa11,并对这3个分离株的培养特性进行了研究.结果表明,Mpc11、Mpc12、Mpa11 3个菌株的固氮酶活性分别为691 nmol乙烯/mg蛋白·h、689 nmol乙烯/mg蛋白·h和1039 nmol乙烯/mg蛋白·h.适宜于在BAP(有氮)固体培养基、BM+NZ和FMS液体培养基上生长.且分别以葡萄糖、丙酮酸钠(含量均为1 g/L)、吐温-20(含量为1 mL/L)为唯一碳源或分别以酪蛋白水解物、酵母抽提物(含量均为0.5 g/L)为唯一氮源的BAP培养基上生长良好;能利用丙酸钠,但利用率低;且均不能利用尿素.Mpc11和Mpa11分离株适宜于在pH5.5～6.5范围内生长,pH7.0以上则菌体生长受到抑制.     

杨梅雌、雄种质遗传关系的RAPD和ISSR分析

为获得与主栽的杨梅品种遗传基础相近的杨梅雄株,文章采用了22个多态的RAPD引物和7个多态的ISSR引物,对浙江杨梅的栽培品种东魁、荸荠种、晚稻杨梅、丁岙梅和早色等10个雌株与17个雄株种质资源间的遗传关系进行了研究。结果表明,不同杨梅产地收集的这17个杨梅雄株种质资源中,雄株与品种间的遗传关系呈规律性,即同一产区的地方品种与当地的雄株间遗传相似程度最高,而同一地区不同雄株与当地主栽品种间的遗传相似程度也有不同。通过UPGMA法进行聚类分析,上述5个杨梅主栽品种分别获得了与其亲缘关系相对接近的雄株,成对遗传相似系数最高为0.958,最低为0.878。