小油桐外植体的KN1基因遗传转化及其超量表达的转基因植株

本研究采用农杆菌介导法将KN1基因遗传转化小油桐,并获得了转基因植株。在研究中分析了农杆菌菌液菌液的浓度、侵染时间和外植体的大小对遗传转化效率的影响以及KN1基因超量表达对转基因植株再生的影响。研究结果表明：以苗龄15d左右的小油桐无菌苗子叶为外植体,农杆菌菌液浓度OD600为0.6～0.8时,侵染8min,外植体大小为（0.8×0.8）～（1.0×1.0）mm时,遗传转化效果最好;对抗性芽及再生植株进行GUS及PCR检测结果表明,KN1基因已经整合到小油桐植物基因组中。KN1基因的超量表达可提高小油桐再生芽分化,影响转化芽及植株的外观形态及叶片的表型,包括芽及植株矮小,茎杆粗壮;叶片缩小,边缘分裂,对称性丧失,无子叶柄等。     

Can Non-fumigant Nematicides Be an Alternative to Fumigation on Carrot Fields?

ABSTRACT

Root-knot nematodes (RKN; Meloidogyne spp.) cause enormous yield reductions in vegetable crops. While nematicides are the most effective method for controlling RKN in carrot (Dacatus carota), the efficacy of non-fumigant nematicides, compared to fumigants, is still not fully understood. The objective of this study was to evaluate the effect of 1,3-dichloropropene, a fumigant nematicide, and fluensulfone, a non-fumigant nematicide, on RKN control and yield of fresh market and processing carrot. Field experiments were conducted in a commercial farm in Lenox, GA. A randomized complete block design (r = 4) was used in a factorial arrangement of 3 nematicide treatments and 2 carrot cultivars. Nematicide treatments were the application of 1,3-dichloropropene, fluensulfone, and untreated control. Carrot cultivars were Baltimore (fresh marketing) and Belgrado (processing). In general, RKN population was low early season, averaging 0.8 RKN 100 cm^?3 of soil. RKN populations increased with crop development and there were significant differences among nematicide treatments. At harvest, RKN populations were lower for fluensulfone (1.1 RKN 100 cm^?3 of soil) and 1,3-dichloropropene (3.2 RKN 100 cm^?3 of soil) compared to Control (26.4 RKN 100 cm^?3 of soil); however, fluensulfone (91,278 kg ha^?1) had higher yield than 1,3-dichloropropene (64,154 kg ha^?1) and Control (61,908 kg ha^?1). Carrot cultivars were similar for RKN population and yield. Overall, the non-fumigant nematicide was more beneficial for carrot production than the fumigant nematicide.     

Negligible contribution from roots to soil-borne phospholipid fatty acid fungal biomarkers 18:2ω6,9 and 18:1ω9

The phospholipid fatty acid biomarkers 18:1ω9, 18:2ω6,9 and 18:3ω3,6,9 are commonly used as fungal biomarkers in soils. They have, however, also been found to occur in plant tissues, such as roots. Thus, the use of these PLFAs as fungal biomarkers in sieved soil, which may still contain small remains of roots, has been questioned. We used data from a recent beech tree girdling experiment to calculate the contribution of roots to these biomarkers and were able to demonstrate that not more than 0.61% of 18:1ω9 and 18:2ω6,9 in sieved soil samples originated from roots (but 4% of 18:3ω3,6,9). Additionally, the abundance of the biomarker 18:2ω6,9 in the soil was found to be highly correlated to ectomycorrhizal root colonization, which further corroborates its fungal origin. PLFA biomarkers were substantially reduced in vital roots from girdled trees compared to roots of control trees (by up to 76%), indicating that the major part of PLFAs measured in roots may actually originate from ectomycorrhizal fungi growing inside the roots. We calculated, that even a near to 50% reduction in fine root biomass - as observed in the girdling treatment - accounted for only 0.8% of the measured decrease of 18:2ω6,9. Our results demonstrate that both 18:1ω9 and 18:2ω6,9 are suitable biomarkers for detecting fungal dynamics in soils and that especially 18:2ω6,9 is a reliable biomarker to study mycorrhizal dynamics in beech forests.     

浙江省严重干旱发生年份的GM（1，1）预测模型

传统灰色GM（1，1）模型对稳定序列的中长期预测效果较好，对变化幅度较大的严重干旱年序列的中长期预测效果较差。本文采用中心逼近式灰色GM（1，1）模型，通过调整m值，使模型精度达到要求，从而建立浙江省严重干旱发生年份的GM（1，1）预测模型。拟合结果表明，该方法对预测浙江省下一个严重干旱发生年有一定的参考价值。     

北京市怀柔区生态用水计算研究

根据生态平衡理论,依据北京市怀柔区的实际情况,划分了北京市怀柔区生态用水类型,并将怀柔区划分为相互独立的二级生态区;计算出怀柔区各项生态用水量。结果为:全区现状生态用水总量为7.19亿m3/a。其中,森林植被生态用水量为4.65亿m3/a,水土保持生态用水量为0.83亿m3/a,城镇绿化生态用水量为0.02亿m3/a,草地生态用水量为1.29亿m3/a,河流生态系统生态用水为0.4亿m3/a。     

番茄侧根原基发生相关基因RSI-1在烟草中功能的初步研究

为探讨番茄(Lycopersiconesculentumvar.cerasiforme)侧根原基发生相关基因RSI-1在形态发育过程中的作用及其在获得具超量侧根的转基因作物的应用前景,研究分析了RSI-1基因在烟草(Nicotianatabacum)中超量、反义抑制和RNA干扰表达后植株形态及转基因植株内侧根发生相关植物激素含量的变化特征。结果显示,RSI-1超量表达后,植株株高下降,叶片数和分支数有明显增加,而RSI-1反义抑制和RNA干扰表达后植株形态及赤霉素、生长素、脱落酸和玉米素及核苷的含量均没有发生显著变化。推测RSI-1的表达可以促进植物分枝的发生,但其在高等植物中的同源性可能较低,利用该基因定向改造弱根系作物时还需结合根特异启动子的应用。     

Two- and three-domain bacterial laccase-like genes are present in drained peat soils

Laccases of fungal origin have been intensively studied due to their importance in various biotechnological applications. There is a constant demand for new laccases with improved properties such as stability at higher temperatures or at an alkaline pH. Growing molecular evidence suggests that laccases may also be widespread in bacteria. While only a handful of bacterial laccases have been purified and characterized, several novel traits have already been discovered (e.g. pH-stability and 2-domain organization of the enzyme as opposed to the usual 3-domain structure of fungal laccases). The aim of this study was to examine the diversity of bacterial laccase-like genes in two types of high-organic peat soil using a cloning and sequencing approach. Gene libraries prepared of small fragments (150 base pairs) revealed an amazing diversity of bacterial laccases. The fragments clustered in 11 major lineages, and one third of the 241 sequences resembled laccase-like genes of Acidobacteria. Additionally, a new primer was used to retrieve several larger fragments of the putative bacterial laccase genes that spanned all four copper-binding sites. Both “conventional” 3-domain laccases and the recently described 2-domain small laccases have been obtained using this approach, demonstrating the potential of the primer. The present study thus contributes to the understanding of the diversity of bacterial laccases and provides a new tool for finding laccase-like sequences in bacterial strains and soil samples.     

基于GF-1影像NDVI年度间相关分析的冬小麦面积变化监测

为实现区域冬小麦种植面积变化的快速监测,减少监测难度,提高监测效率和精度,该文提出一种基于年际NDVI相关关系的监测方法(relationship analysis of normal difference vegetation index,rNDVI)。选择河北省黄骅市、孟村县、海兴县3个县市为研究区,基于2014年4月14日、2017年4月26日两个时期的GF-1/WFV数据,基于rNDVI方法,通过将样本点两年度的NDVI值构建二维空间,采用最小二乘法拟合的方法获得不变地物点的上下包络线方程,进而得到冬小麦变化区域的监测阈值,提取冬小麦种植增加和减少区域,实现对研究区域的变化监测。结果表明,采用rNDVI算法总体精度分别为90.60%,Kappa系数为0.84,相比传统的先最大似然分类后再提取冬小麦种植变化区域的方法,总体精度与Kappa系数分别提高了6.6个百分点和16.7%。对冬小麦增加区域、冬小麦减少区域的变化监测结果进行分析,发现基于rNDVI的变化监测方法可以有效提高裸地、线状道路、破碎的冬小麦地块等区域的变化识别能力,提高监测精度。同时分别利用2014年3月1日和2017年3月12日、2014年5月17日与2017年5月20日两对GF-1/WFV数据进行基于rNDVI的冬小麦变化区域监测,结果表明3月份的监测精度较低,主要是由于3月份冬小麦长势尚不明显,5月份与4月份的总体精度相近,主要是由于5月份冬小麦NDVI已较高,易于识别。上述研究结果表明,基于rNDVI的冬小麦变化快速监测方法可以有效监测区域冬小麦种植面积的变化情况,算法简单高效,且能够在种植结构相对单一的冬小麦分布区域保持较高精度,能够满足农情遥感监测信息快速获取的需要。     

HJ-1卫星延寿期的CCD影像质量评价与可用性分析

HJ-1卫星发射升空投入运行以来,已在灾害与环境的快速监测与预报领域发挥了重要作用。HJ-1卫星目前已经成功运行3a多,属于超期服役状态。为了评价延寿期影像质量,该文从影像的几何校正精度、灰度特征和纹理特征3个方面对延寿期HJ-1A-CCD影像进行分析,并与正常寿命运行期的HJ-1ACCD影像、同时期的Landsat7 ETM+影像进行比较,分析结果表明:延寿期HJ-1A-CCD影像质量虽然有一定程度的下降,但其与正常寿命期影像质量接近,仍能较好地描述丰富的地物类型及地物细节信息,可以像正常寿命期影像一样,有效地用于环境监测、灾害监测、国土资源管理、城市规划、农业应用等方面。