Nitrogen addition enhances home-field advantage during litter decomposition in subtropical forest plantations

Nitrogen (N) exerts strong effects on litter decomposition through altering microbial abundance and community composition. However, the effect of N addition on plant–soil interactions such as home-field advantage (HFA: enhanced decomposition at a home environment compared to a guest environment) in relation to litter decomposition remains unclear. To fill this knowledge gap, we conducted a reciprocal litter transplant plus N addition experiment in Mytilaria laosensis and Cunninghamia lanceolata plantations for two years in subtropical China where anthropogenic N input is amongst the highest in the world. We found positive HFA effects (in which the calculation incorporates litter of both species) with litter mass loss 11.2% faster at home than in the guest environment in the N addition (50 kg N ha⁻¹ yr⁻¹) treatment, but no significant HFA effects were found in the control treatment. The magnitude of the HFA effect on carbon (C) release increased with N addition, while that on N release decreased. The HFA effects on phosphorus, potassium, calcium, sodium, and magnesium release were positive overall, but varied through time and the magnitude of the effects were different among elements. The greater HFA effects in the N addition treatment were associated with greater differences in microbial biomass and community composition between home and guest environments than in the control treatment. Our results indicate that anthropogenic N enrichment could lead to enhanced HFA effects, through modification of microbial communities, and thereby affect C sequestration and N cycling in subtropical forests.     

北方树木移栽技术初探

在多年绿化施工管理的研究和实践基础上,对北方树木移栽技术进行探索,提出"选好树、挖好坑,整好冠、浇好水,支好架、绑好干,施好肥、喷好药"的树木移裁配套技术方案.     

不同光照对广玉兰1年生移栽苗的生长影响

通过设置4个不同的[光]照度（100％、75％、47％、25％）研究了广玉兰Magnolia grandiflora1年生移栽苗的生长情况。结果表明，在第四纪红色黏土上，广玉兰在不同的[光]照度下成活率较高，均达91％以上，以47％时最高，达95．83％；苗高总生长量表现为47％〉75％〉25％〉100％，47％时净增长量最大；地径总生长量表现为47％〉100％〉75％〉25％，同样，47％时净增长量最大；叶的生长大小相对一致；叶绿素含量、净光合速率、蒸腾速率的变化也相对稳定，无太大反差。综合评定结果表明，在第四纪红色黏土上，广玉兰移栽苗对不同[光]照度具有不同的可塑性和适应性，光强为47％时生长最好，适当的遮荫更能促进苗木的生长。     

花毛茛组培苗移栽试验初探

通过在3种基质和2种基质不同配比中进行花毛茛组培苗移栽试验,发现腐殖土对有根苗移栽成苗率达82%,植株长势较好;在珍珠岩与腐殖土4种配比中,以1∶3的基质配比较适宜花毛茛组培苗移栽,有根苗成活率达90%,无根苗成活率达88%,长势好,病害少;生根粉处理无根苗后,在珍珠岩中栽培成活率有明显提高,植株长势较差,在腐殖土中栽培成活率及植株长势没有明显变化。     

牡丹离体培养与快速繁殖研究进展

从愈伤组织培养、胚培养、花药与花粉培养以及器官培养几方面论述了牡丹离体培养的研究现状，并对今后的研究提出了一些建议，认为快速繁殖技术要应用于牡丹的产业化生产。必须提高牡丹试管苗的生根质量，并探寻合适的移栽驯化方法。     

Measurement system of whole-canopy carbon dioxide exchange rates in grafted cucumber transplants in which scions were exposed to different water regimes using a semi-open multi-chamber

A continuous CO₂ measurement system was developed to monitor the CO₂ exchange rate of the whole canopy of grafted transplants using semi-open multiple chambers. Air heating or cooling and humidification inside a healing box were under control, if needed. To test the system, the gas exchange rate of the cucumber (Cucumis sativus L.) transplants grafted onto pumpkin (Cucurbita maxima cv. ‘New-Shintozwa’) was analysed. During the healing and acclimatisation of the grafted cucumber plants, the air temperature in the box remained constant at night but ranged above 1 °C of a set value under high humidity in daytime. The relative humidity was kept within the set point during the daytime, and it nearly reached 100% at night when not controlled. The cucumber seedlings were exposed to different water stresses before grafting, and the water potentials of each treatment were −0.579 (non-stressed), −0.814 (mildly water-stressed), and −0.870 MPa (strongly water-stressed) on grafting. At the water-stressed scions, leaf expansion was inhibited by 30.9–53.3% compared with the non-stressed scions. Therefore, the gas exchange rates of the strongly water-stressed scions based on the leaf area were decreased to 72.7% compared with the non-stressed scions. After grafting, the apparent photosynthesis of the transplants of all treatments was negative, with higher respiration in the strongly water-stressed scions during the initial period of healing. However, they turned to positive values and exceeded those of the non-stressed scions from three days after grafting. This result provides critical information that the water column is physiologically connected between the stock and scion within two days after grafting. As a result of water stress, the leaf area and dry weight of the transplants in the strongly water-stressed scions were inhibited by 67.5% and 83% compared with the non-stressed scions at the end of acclimatisation. In contrast, the relative growth rate and graft-take of the strongly water-stressed transplants were slightly increased, which suggests that the water stress prior to grafting alleviated the water demand of the scion. This system may provide useful information for diagnosis at the early stage by monitoring the whole canopy's photosynthesis over a long term.     

甜菜机械化种植技术及配套机械

通过对甜菜作物耕作、播种技术特殊需求的分析,列举了我国甜菜主产区耕作、播种的几种形式和配套机具选用原则,提出了我国甜菜主产区耕作、播种机械存在的问题和解决方法。调整机械作业标准、改善耕整地作业质量和推广联合耕整地、精量播种技术是实现甜菜全程机械化的发展方向。     

辣木组织培养试验

辣木种子消毒试验结果表明,用15%H2O2浸泡6～8 h、0.1%升汞处理25 min后将种子接种于MS培养基中,10d后种子发芽率达78.2%.组培试验结果表明,在MS 6-BA 0.10 mg/L KT 0.50 mg/L培养基中,辣木茎段产生大量不定芽,繁殖系数为6.0倍,芽生长良好;将不定芽切割后接种于MS 6-BA 0.10 mg/L KT 0.50 mg/L培养基中,增殖倍数可达4.8倍;在1/2MS IBA 0.1 mg/L培养基中,小苗生根率高达98%,平均单株生根数和根长分别为4.8条和2.0 cm;将生根苗移栽于珍珠岩 营养土(1∶2,V/V)的混合基质中,30 d后移栽成活率达80%.     

贵州黑山羊胚胎移植手术不同麻醉方法比较

为了筛选适合于贵州黑山羊胚胎移植手术的麻醉方法,试验以贵州黑山羊为试验动物,比较了速眠新Ⅱ注射液2种麻醉方法（肌肉麻醉和静脉麻醉）对山羊生理指标,麻醉山羊的诱导期、麻醉期、苏醒期,麻醉苏醒后山羊的采食、反刍及精神状况的影响。结果表明：2种麻醉方法下,麻醉效果优、良的山羊数量和生理指标无明显差异;速眠新Ⅱ注射液静脉注射麻醉时,山羊的诱导期、麻醉期和苏醒期均较短,在苏醒后0.5 h,90.0%的山羊可以采食,83.3%的山羊可以反刍,93.3%的山羊精神状况良好;苏醒后1 h基本上全部可以恢复正常;采用静脉注射麻醉山羊进行胚胎移植手术,速眠新Ⅱ注射液用药剂量小,且安全、有效,明显优于肌肉注射。     

红掌组培快繁中若干问题的探讨

通过红掌组培快繁生产实践认为:正确选择品种和外植体、简化培养过程是组培快繁生产的关键,而降低成本、提高瓶苗移栽管理技术是实现高效益组培苗生产的根本途径。