华北落叶松针叶碳、氮、磷含量及化学计量比的季节变化

【目的】碳(C)、氮(N)和磷(P)在林木的生长发育中有着重要作用,三者的含量变化和元素比值控制着林木的营养和生长状况。本研究主要分析了秦岭山区同一树种不同林龄叶片的C、N、P含量及化学计量比随季节变化的规律,为林木施肥管理提供依据。【方法】在林木生长季的不同月份(2012年5月到10月每月中旬),对秦岭5年生(5a)、10年生(10 a)、20年生(20 a)3种林龄的华北落叶松针叶进行定期采集,并测定不同月份各林龄针叶的C、N、P含量和化学计量比值,对不同林龄不同生长季华北落叶松针叶的C、N、P及C∶N、C∶P、N∶P的动态变化进行分析,并对其C∶N与氮含量、C∶P与磷含量进行相关性分析。【结果】1)3种林龄针叶的碳含量从生长初期(5 6月)到生长旺盛期(7 8月)逐渐增加,生长末期(8 9月)逐渐降低,但到落叶期(10月)又小幅回升。2)3种林龄华北落叶松针叶的氮含量在整个生长季内(5 10月)均呈现先降低后升高再降低的趋势,各林龄针叶氮含量升高和降低的时间存在差异,5 a和20 a林龄的针叶N含量从6月到生长旺盛期(7月、8月)基本上保持上升趋势,而10 a林龄针叶的氮含量6 7月份先逐渐降低,7 9月份急剧升高,落叶前期到落叶(9 10月)这段时间3种林龄针叶的N含量均急剧下降为最低值。3)3种林龄针叶磷含量在整个生长季节内的变化趋势基本一致,均先降低后升高再降低最终维持稳定。4)5 a、10 a和20 a林龄的华北落叶松在生长季节内针叶的C∶N变化范围分别为21.83 56.42、18.4358.49和22.54 87.83,变异系数分别达到了37.74%、42.05%和68.42%,随着树龄的增长其变异系数逐渐增大。5)5 a、10 a、20 a林龄的华北落叶松在生长季节内针叶C∶P的变化范围分别为169.17 402.85、180.54 395.01和213.02 398.75,变异系数依次为31.35%、31.43%和22.88%。6)针叶的N∶P,5 a、10 a、20 a在生长季节内的变化范围分别为6.77 15.42、6.38 20.13和4.44 14.45,变异系数分别为39.65%、50.86%和33.03%。7)各林龄针叶的C、N、P平均含量以及各比值之间的差异均不显著(P0.05)。【结论】3种林龄的华北落叶松针叶的C∶N、C∶P均与相应的N、P含量呈显著负相关(P0.05),随着N、P含量的变化以对数方程的形式减小。同时发现,氮是秦岭地区幼、中林龄华北落叶松生长的主要限制性因子,土壤中的氮养分不足会制约林木的生长,因此对本研究区的土壤应及时补充氮肥以满足华北落叶松正常生长的营养需求。     

厚皮甜瓜新品种红宝玉的选育

红宝玉是以10R15 为母本、10R8 为父本选育而成的中熟厚皮甜瓜一代杂种。植株长势稳健，抗病抗逆性强。全生育期95～110 d（天），果实发育期30～35 d（天）。果实短椭圆形，成熟后果面乳白色，单果质量约1.5 kg，果肉橘红色，肉厚3.5～4.0 cm，腔小不发酵，中心可溶性固形物含量17.5%，肉质紧脆，不脱蒂，耐贮耐运。平均每667 m²产量3 600 kg 左右。适宜在山东、河北、陕西、安徽等地春季保护地设施栽培。     

黄土坡面结皮对土壤水稳性团聚体的稳定性和可蚀性的影响

为了探析微地形下土壤受雨滴打击后产生的结皮类型及团聚体组成差异。通过人工模拟降雨,研究坡面不同位置的结皮土壤水稳性团聚体分布特征、稳定性以及土壤可蚀性的变化情况。结果表明：（1）土壤水稳性团聚体以大团聚体（粒径>0.25 mm）含量为指标,原状土、结构结皮、沉积结皮、过渡带结皮>0.25 mm粒级的水稳性团聚体分别占37.28%、43.58%、36.69%、40.34%;（2）以降雨历时5 min为例,原状土、结构结皮、沉积结皮、过渡带结皮的水稳性团聚体的破坏率分别为：51.49%、46.00%、62.76%、51.02%;（3）原状土、结构结皮、沉积结皮、过渡带结皮的水稳性团聚体的平均重量直径分别为：0.15、0.20、0.14、0.17 mm;（4）原状土、结构结皮、沉积结皮、过渡带结皮土壤可蚀性K值的大小分别为：0.223、0.200、0.229、0.205。微地形下产生结皮差异使得水稳性团聚体分布有所区别,因此土壤水稳性团聚体稳定性和可蚀性存在差异。     

不同密度紧凑型油菜的源库特征及与收获指数的相关研究

旨在为油菜株型育种和机械化栽培提供理论和技术依据。选用3个不同类型的紧凑型油菜常规品种,以松散型油菜杂交种‘秦优7号’为对照,研究了在15万、30万、45万、60万、75万、90万株/hm²密度下各品系的库源特征及其与收获指数的关系。结果表明,紧凑型油菜单株在不同密度下的库源特征与对照松散型相同,单株根、茎、枝、壳干重,角粒数和单株角果数随种植密度的增加而降低,且低密度显著高于高密度;千粒重随密度的变化不大。紧凑型油菜的生物学产量和经济产量随种植密度的增加而增加,松散型油菜随种植密度的增加而下降。说明紧凑型油菜适宜密植和机械化收获。收获指数对密度的响应在两类型品种表现一致,最低密度15万株/hm²增加到30万株/hm²时达到峰值,以后随着种植密度的继续增加而降低。收获指数与茎+枝+壳干重之和,与库性状角粒数、角果数、千粒重、单株产量,与库源关系的粒根比、粒茎比、粒枝比、粒壳比显著正相关,说明要提高收获指数不仅要扩“源”增“库”,还要协调库源的合理分配比例。     

华山松大小蠹2个甲羟戊酸路径基因的克隆与表达

香叶基二磷酸合酶/法尼基焦磷酸（G/FPPS）和异戊二烯焦磷酸异构酶（IDI）是单萜和倍半萜生物合成途径分支点的关键酶。通过克隆华山松大小蠹DaG/FPPS和DaIDI基因的全长序列，预测基因和编码蛋白的性质、结构和功能，并对序列特征和不同发育时期（幼虫、蛹、初羽化期成虫和扩散期成虫）以及不同组织（头、前中肠、后中肠、后肠和剩余躯体）DaG/FPPS和DaIDI表达的研究，旨在揭示DaG/FPPS和DaIDI在华山松大小蠹信息化学物质合成中的分子调控机制。采用RT-PCR和RACE克隆华山松大小蠹DaG/FPPS和DaIDI基因，DNAStar、Blast、ExpasyProtscale、SignalP 4.1、PSORT和TargetP等多种生物信息学方法对基因全长cDNA序列、基本理化性质、系统进化关系、信号肽和蛋白亚细胞定位等进行分析。用Real-time PCR检测DaG/FPPS和DaIDI在华山松大小蠹不同发育时期和不同组织中的表达。结果表明，克隆获得华山松大小蠹香叶基二磷酸合酶/法尼基焦磷酸DaG/FPPS和异戊二烯焦磷酸异构酶DaIDI全长cDNA序列，分别命名为DaG/FPPS和DaIDI，DaG/FPPS编码的氨基酸序列与山松大小蠹DpF/GPPS相似度最高达95%，氨基酸序列含有一个RALS 四肽基序、7 个异戊烯基转移酶保守区（Ⅰ-Ⅶ）和2个典型的DD**D的天冬氨酸富含区；DaIDI编码的氨基酸序列与山松大小蠹IDI相似度最高，达到92%。Expasy Protscale结果表明DaG/FPPS蛋白疏水性氨基酸明显多于亲水性氨基酸，推测其为疏水性蛋白，而DaIDI蛋白亲水性氨基酸数量大于疏水性氨基酸，故推测DaIDI为亲水性蛋白，有较好的水溶性。信号肽预测结果表明，DaG/FPPS和DaIDI均不含信号肽，TargetP结果表明，DaG/FPPS和DaIDI蛋白含线粒体靶向肽，结合PSORT结果推测DaG/FPPS和DaIDI均定位于线粒体。华山松大小蠹DaG/FPPS和DaIDI在不同发育时期和不同组织中均有表达，其中完全羽化期与扩散期成虫保持一致，该阶段表达量最高，不同组织中前中肠表达量最高。     

葡萄‘小白玫瑰’及其突变品种‘小红玫瑰’果皮颜色变异机理分析

‘小红玫瑰’葡萄是源自于‘小白玫瑰’的突变品种,二者都是优良的酿酒葡萄品种,但其果实颜色变异的分子机理尚不清楚。用12对SSR(Simple sequence repeats)荧光标记特征引物对两品种进行分析,结果表明这些位点在二者之间无差别。对色泽变异决定基因Vvmyb A1的基因型进行分析,‘小白玫瑰’仅检测到含有插入逆转座子Gret1(grapevine retrotransposon 1)的VvmybA1a,说明其为VvmybA1a/VvmybA1a纯合体;而‘小红玫瑰’检测到了Vvmyb A1a和残留Gret1 3′-LTR(long terminal repeat)的VvmybA1b,说明其为VvmybA1a/VvmybA1b的杂合体。花色苷合成相关基因的表达分析表明,VvmybA1、UFGT、F3′5′H、CHS、GST和OMT在‘小红玫瑰’及有色对照品种‘黑比诺’中大量表达,而在‘小白玫瑰’和无色对照品种‘白比诺’中几乎不表达。通过HPLC–ESI–MS/MS对花色苷主要成分进行测定,结果表明矢车菊素3–O–葡萄糖苷(CyG)、矢车菊素3,5–O–双葡萄糖苷(Cy2G)、飞燕草素3–O–葡萄糖苷(DpG)、锦葵色素3–O–葡萄糖苷(MvG)、芍药色素3–O–葡萄糖苷(PnG)和矮牵牛色素3–O–葡萄糖苷(PtG)等6种花色苷在有色品种‘小红玫瑰’和‘黑比诺’果皮中的含量均显著高于无色品种,花葵素3–O–葡萄糖苷(Pg G)、花葵素3,5–O–双葡萄糖苷(Pg2G)在有色/无色品种间无显著差异,且含量很低。说明‘小红玫瑰’的着色是由于转录因子基因Vvmyb A1及其调控结构基因的表达引起的,而无功能的VvmybA1a等位基因突变为有功能的VvmybA1b等位基因是其果皮颜色变异的遗传学原因。     

Development of IP and SCAR markers linked to the yellow seed color gene in Brassica juncea L.

Previous studies showed that the yellow seed color gene of a yellow mustard was located on the A09 chromosome. In this study, the sequences of the molecular markers linked to the yellow seed color gene were analyzed, the gene was primarily mapped to an interval of 23.304 to 29.402M. Twenty genes and eight markers’ sequences in this region were selected to design the IP and SCAR primers. These primers were used to screen a BC₈S₁ population consisting of 1256 individuals. As a result, five IP and five SCAR markers were successfully developed. IP4 and Y1 were located on either side of the yellow seed color gene at a distance of 0.1 and 0.3 cM, respectively. IP1, IP2 and IP3 derived from Bra036827, Bra036828, Bra036829 separately, co-segregated with the target gene. BLAST analysis indicated that the sequences of newly developed markers showed good collinearity with those of the A09 chromosome, and that the target gene might exist between 27.079 and 27.616M. In light of annotations of the genes in this region, only Bra036828 is associated with flavonoid biosynthesis. This gene has high similarity with the TRANSPARENT TESTA6 gene, Bra036828 was hence identified as being the gene possibly responsible for yellow seed color, in our research.     

Contribution of green manure legumes to nitrogen dynamics in traditional winter wheat cropping system in the Loess Plateau of China

Excessive application of N fertilizer in pursuit of higher yields is common due to poor soil fertility and low crop productivity. However, this practice causes serious soil depletion and N loss in the traditional wheat cropping system in the Loess Plateau of China. Growing summer legumes as the green manure (GM) crop is a viable solution because of its unique ability to fix atmospheric N₂. Actually, little is known about the contribution of GM N to grain and N utilization in the subsequent crop. Therefore, we conducted a four-year field experiment with four winter wheat-based rotations (summer fallow-wheat, Huai bean–wheat, soybean–wheat, and mung bean–wheat) and four nitrogen fertilizer rates applied to wheat (0, 108, 135, and 162 kg N/ha) to investigate the fate of GM nitrogen via decomposition, utilization by wheat, and contribution to grain production and nitrogen economy through GM legumes. Here we showed that GM legumes accumulated 53–76 kg N/ha per year. After decomposing for approximately one year, more than 32 kg N/ha was released from GM legumes. The amount of nitrogen released via GM decomposition that was subsequently utilized by wheat was 7–27 kg N/ha. Incorporation of GM legumes effectively replaced 13–48% (average 31%) of the applied mineral nitrogen fertilizer. Additionally, the GM approach during the fallow period reduced the risk of nitrate-N leaching to depths of 0–100 cm and 100–200 cm by 4.8 and 19.6 kg N/ha, respectively. The soil nitrogen pool was effectively improved by incorporation of GM legumes at the times of wheat sowing. Cultivation of leguminous GM during summer is a better option than bare fallow to maintain the soil nitrogen pool, and decrease the rates required for N fertilization not only in the Loess Plateau of China but also in other similar dryland regions worldwide.     

Detecting interactive effects of N fertilization and heat stress on maize productivity by remote sensing techniques

The objective of this study was to compare the performance of two different remotely sensed techniques in detecting the effects of terminal heat stress and N fertilization on final maize aerial biomass (AB) and grain yield (GY). The study was conducted under field conditions for two consecutive growing seasons. Six N treatments combining three doses [0, 100, 200 Kg N ha⁻¹] and two timings [at V4 and at 15 days before silking] were applied. Within each N treatment three heat treatments were applied (pre-flowering, post-flowering and the control treatment at ambient air temperature). Remote sensing measurements were taken with a multispectral band camera to measure the normalized difference vegetation index (NDVI) and a digital Red/Green/Blue (RGB) camera to measure the normalized green red difference index (NGRDI). Both indices failed to predict the GY of pre-flowering heat-treated plants due to grain set establishment problems that could not be detected by vegetation indices which are designed to capture differences in green canopy area. In contrast, both the NGRDI and the NDVI correlated positively with GY and AB in the control heat treatment and to a lesser extent in the post-flowering heat treatment. Under the control heat treatment, the NGRDI exhibited higher correlations with AB and GY than the NDVI across the N fertilization treatments. Since the NGRDI is formulated based only on the reflectance in the visible regions (VIS) of the spectrum (Green and Red) without dependence on the near infrared regions (NIR), it performs better than the NDVI. This is because it overcame the reported saturation patterns at high leaf area index and was more efficient at capturing even small differences in leaf colour (chlorophyll content) due to the different applied N treatments. Also, the NGRDI seemed to be a more seasonally independent parameter than the NDVI, which is more affected by temporal variability within the field, and thus the NGRDI predicted AB and GY better than the NDVI when combining the data of the two growing seasons.     

苹果赤霉素信号转导因子MdGAMYB的克隆和表达分析

以‘长富2号’苹果为试验材料,从其短枝顶芽中克隆得到1个赤霉素信号转导因子MdGAMYB,对其进行生物信息学和表达分析。结果表明,MdGAMYB的开放阅读框(ORF)长度为1 656bp,编码551个氨基酸,蛋白质分子量为59.741 kD。生物信息学分析表明MdGAMYB编码的蛋白存在多个糖基化位点和磷酸化位点;序列分析表明,Md GAYMB和其他物种的GAMYB蛋白有很高的相似性,均含有保守的R2R3 DNA结合域和GAMYB家族所特有的Box1,Box2和Box3保守区域;系统进化分析表明,Md GAYMB与梨、梅花、草莓、枣和葡萄等的GAMYB蛋白具有较高的同源性。实时荧光定量PCR分析表明,Md GAYMB具有组织表达特异性,在叶片、花和芽中的表达量较高。外源GA3处理抑制了花芽孕育和翌年成花,抑制MdGAMYB的表达。在易成花品种‘烟富6号’中的表达量高于难成花品种‘长富2号’。