微咸水膜下滴灌对土壤水盐分布及加工番茄产量的影响

为探明微咸水膜下滴灌对土壤水盐分布及加工番茄生长和产量的影响,通过大田小区试验,设置灌水矿化度和灌水定额两个因素,其中3个灌溉水矿化度水平分别为S1:1 g·L~(-1)、S2:3 g·L~(-1)和S3:5 g·L~(-1),3个灌水定额分别为W1:305 m~3·hm~(-2)、W2:458 m~3·hm~(-2)和W3:611 m~3·hm~(-2),来进一步寻求适宜本地区加工番茄生长的微咸水膜下滴灌灌溉制度。结果表明:覆膜微咸水滴灌条件下土壤含水量垂直方向的变化趋势表现为0～20 cm土层随深度增加含水量逐渐降低、20～100 cm土层随深度增加含水量逐渐增大、60～100 cm范围内土层剖面含水量最大的分布规律;土壤含盐量随着灌水矿化度的增大而增加,且随着灌水量的增加土壤盐分逐渐向水平距滴灌带35 cm处聚集。灌水矿化度超过3 g·L~(-1)时加工番茄株高、茎粗均受到一定程度的抑制作用,但对产量影响不大。本文通过试验得出:灌水定额为611 m~3·hm~(-2)、矿化度为1 g·L~(-1)处理为本地区最佳微咸水膜下滴灌处理,加工番茄生长健壮且产量最高,达到127 613.2 kg·hm~(-2);同时认为,在我国淡水资源比较缺乏的新疆地区可以考虑采用灌水定额458 m~3·hm~(-2)和灌水矿化度3～5 g·L~(-1)的微咸水对盐分中等敏感的加工番茄进行灌溉。     

基于无人机遥感的棉花主要生育时期地上生物量估算及验证

利用棉花主要生育时期的无人机近红外影像数据，提取4种不同的植被指数，通过与棉花地上生物量的实测值建立拟合关系，分析了不同植被指数在棉花各生育时期的估算效果并对其进行了验证。结果表明，随棉花生长，归一化植被指数（NDVI）、宽动态植被指数（WDRVI）、比值植被指数（RVI）和差值植被指数（DVI）均从苗期开始显著增加，其后则表现为基本稳定的“饱和”现象，但棉花实测生物量在不同生育期均有显著差异。植被指数与棉花实测生物量的拟合结果显示：NDVI和DVI的二元线性拟合模型对苗期生物量拟合效果最佳（R²=0.84，RMSE=0.13 kg·m^-2）；WDRVI和DVI的二元线性拟合模型对花蕾期生物量拟合效果最佳（R²=0.87，RMSE=0.52 kg·m^-2）；RVI的非线性拟合模型对花铃期生物量拟合效果最佳（R²=0.79，RMSE=0.95 kg·m^-2）；WDRVI和RVI的二元线性拟合模型对盛铃期生物量的拟合效果最佳（R²=0.86，RMSE=0.96 kg·m^-2）。     

Dietary supplementation with Bacillus subtilis LT3‐1 enhance the growth,immunity and disease resistance against Streptococcus agalactiae infection in genetically improved farmed tilapia,Oreochromis niloticus

A feeding trial was conducted to investigate the effect of different levels of Bacillus subtilis LT3‐1 in diets on growth, immune parameters, intestinal morphology and disease resistance in genetically improved farmed tilapia, Oreochromis niloticus. Fish (46.91 ± 0.17 g) were fed with a basal diet supplemented with B. subtilis LT3‐1 at 0 (B0), 3.8 × 10¹⁰ (B1), 7.6 × 10¹⁰ (B2), 1.14 × 10¹¹ (B3) and 1.52 × 10¹¹ (B4) CFU kg^?1 for 6 weeks. The results showed that the weight gain of fish in B1 group was significantly enhanced compared to that in B0 group (p < 0.05). The addition of B. subtilis significantly affected serum biochemical indices (total protein, albumin, aspartate aminotransferase, alkaline phosphatase). Besides, the haematocrit, total counts of red and white blood cells, as well as the serum catalase and lysozyme activities, were increased, whereas the serum malondialdehyde, the serum immunoglobulin M and complement three contents were reduced. Parameters for intestinal morphology suggested a healthier intestine for the fish fed B. subtilis‐supplemented diets than fish fed the control diet. The survival rate after Streptococcus agalactiae challenge increased in tilapia fed with B. subtilis. The present study demonstrated B. subtilis can effectively improve growth, immunological status and resistance against S. agalactiae infection in tilapia farming.     

Effects of antimicrobial peptides on growth,morphology of foregut villi and related genes mRNA expression in the common carp (Cyprinus carpio)

A 60‐day feeding trial was conducted to examine the effects of different levels (0, 100, 200, 400 and 600 mg/kg) of antimicrobial peptides on growth, protease activity of foregut, the morphology of foregut villi and related genes mRNA expression level in the common carp (Cyprinus carpio). The results showed that the feed of antimicrobial peptides promote common carp growth, and the optimal dosage of antimicrobial peptides is 200–333 mg/kg in the common carp feed. The protease activity of 200 and 400 mg/kg groups were significantly higher than the control and other groups (p < 0.05). The foregut villus height with 100, 200 and 400 mg/kg antimicrobial peptide groups were significantly higher than control group (p < 0.05). The crypt depth of 200 and 400 mg/kg antimicrobial peptide groups were significantly lower than control group (p < 0.05). The ratio of villus height and crypt depth of 100, 200 and 400 mg/kg antimicrobial peptide groups were significantly higher than control group (p < 0.05). The ratio with 600 mg/kg group was significantly lower than the control group (p < 0.05). The IGF‐I gene expression level of 200 mg/kg and 400 mg/kg groups were significantly higher than the control group and 600 mg/kg group (p < 0.05). The IL‐1β gene expression level of 100 mg/kg and 200 mg/kg groups were significantly higher than the control group (p < 0.05). These results indicated up‐regulation of growth and immune related genes in antimicrobial peptides fed common carp. Correlation analysis showed that IGF‐I mRNA and IL‐1β mRNA were positively correlated with SGR. IL‐1β mRNA and FCR were significantly negative correlated. It indicated that growth and immune gene common regulated the growth of the carp under antimicrobial peptides intervention. In conclusion, antimicrobial peptides can improve growth and related genes mRNA expression in the common carp. Further studies using molecular biological technique or immunologic methods are required to conclude that antimicrobial peptides are beneficial in common carp.     

Effects of five compound attractants in high plant‐based diets on feed intake and growth performance of juvenile turbot (Scophthalmus maximus L.)

An experiment was conducted to evaluate the effects of five attractants on feed intake, growth performance and appetite‐regulating genes expression for juvenile turbot (Scophthalmus maximus L.). Fish were fed with seven diets: fish‐meal‐based diet (FM), fermented soybean meal replacing 45% fish meal (FSBM) and other diets with 1% compound attractant A (CA‐A) consisting of amino acids, compound attractant B (CA‐B) consisting of quaternary ammonium bases, compound attractant C (CA‐C) consisting of nucleotides, compound attractant G (CA‐G) consisting of the combination of CA‐A, CA‐B and CA‐C and blue mussel protein hydrolysate (BMH) on the basis of FSBM diet respectively. Daily feed intake in CA‐A group was significantly higher, but that in CA‐B group was significantly lower than FSBM group. Similarly, specific growth rate was significantly enhanced in CA‐A and CA‐G groups and were significantly decreased in CA‐B group. Protein efficiency ratio and protein retention in CA‐B group were significantly lower than FSBM group. Furthermore, BMH supplement increased the mRNA expression of Ghrelin in the intestine of fish. These results showed that CA‐A and CA‐G supplement could enhance growth in plant‐based diets, but CA‐B supplement had the opposite effect, which might be associated with lower feed intake and lower feed utilization.     

江汉平原中山杉引种造林试验研究

通过在江汉平原开展中山杉6个品系的引种造林试验。结果表明,引进的6个品系中山杉无严重病虫害发生,各生长指标均大于池杉,11 a生中山杉平均胸径为17.61 cm、树高为11.06 m、材积为0.1297 m^3,表明中山杉在江汉平原的引种试验基本成功,其中中山杉502和中山杉118最为突出,适合在江汉平原推广造林,丰富江汉平原造林树种。     

Relay-intercropping soybean with maize maintains soil fertility and increases nitrogen recovery efficiency by reducing nitrogen input

Optimized nitrogen(N)management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilization can help in dissecting the mechanisms underlying N uptake and utilization in legume-nonlegume intercropping systems.An experiment was performed with three planting patterns:monoculture maize(MM),monoculture soybean(SS),and maize-soybean relay intercropping(IMS),and three N application levels:zero N(NN),reduced N(RN),and conventional N(CN)to investigate crop N uptake and utilization characteristics.N recovery efficiency and 15N recovery rate of crops were higher under RN than under CN,and those under RN were higher under intercropping than under the corresponding monocultures.Compared with MM,IMS showed a lower soil N-dependent rate(SNDR)in 2012.However,the SNDR of MM rapidly declined from 86.8%in 2012 to 49.4%in 2014,whereas that of IMS declined slowly from 75.4%in 2012 to 69.4%in 2014.The interspecific N competition rate(NCRms)was higher under RN than under CN,and increased yearly.Soybean nodule dry weight and nitrogenase activities were respectively 34.2%and 12.5%higher under intercropping than in monoculture at the beginning seed stage.The amount(Ndfa)and ratio(%Ndfa)of soybean N2 fixation were significantly greater under IS than under SS.In conclusion,N fertilizer was more efficiently used under RN than under CN;in particular,the relay intercropping system promoted N fertilizer utilization in comparison with the corresponding monocultures.An intercropping system helps to maintain soil fertility because interspecific N competition promotes biological N fixation by soybean by reducing N input.Thus,a maize-soybean relay intercropping system with reduced N application is sustainable and environmentally friendly.     

食源性单核细胞增生李斯特菌lmoF2365_0037基因克隆及序列分析

为了对食源性单核细胞增生李斯特菌LM5567的lmoF23650037基因进行克隆和序列分析。试验利用PCR方法对lmoF23650037基因进行扩增,连接pMD19-T载体进行克隆,筛选阳性菌株进行测序比对分析。结果显示:扩增获得的lmoF23650037基因序列长为548 bp,克隆得到lmoF23650037基因的阳性转化子;生物信息学分析表明:lmoF23650037蛋白属于跨膜蛋白,无信号肽序列;二级结构中无规则卷曲和延伸链比例较大,分别是46.31%和32.89%;序列比对结果表明,LM5567株lmoF23650037基因核苷酸序列与02-6680株(4b,奶酪,加拿大)、10-0811株(1/2b,螃蟹,加拿大)、10-0809株(4b,粪便,加拿大)、81-0558株(4b,脑脊髓液、加拿大)、02-1103株、02-1792(4b,奶酪,加拿大)、81-0861株(4b,卷心菜,加拿大)相似性均为100%;LM5567 lmoF23650037基因编码的氨基酸序列与上述菌株相似性均为93.3%。本试验成功克隆了lmoF23650037基因,为进一步探究lmoF23650037基因的功能奠定了基础。     

旱碱地增施叶面肥对减氮棉田冠层光分布及产量的影响

为了研究机采种植模式下不同水平减施氮肥后增施叶面肥对棉花花铃期冠层光分布、叶面积指数及与产量的影响，旱碱地条件下，设置0（CK）、60（N1）、90（N2）、120（N3）、150（N4）、180（N5，当地常规施氮量）、225 kg·hm^－2 （N6）7个施氮水平，其中N1～N4喷施叶面肥4次，测定花铃期群体叶面积指数（Leaf area index, LAI）、冠层光分布和籽棉产量。结果表明：与当地常规施氮量相比，减施（60～150 kg·hm^－2）氮肥后，棉花花铃期叶面积指数降低0.7%～5.5%，冠层光总截获率降低0.2～1.7百分点，冠层光透射率升高0.2～0.8百分点；各减施氮肥处理群体叶面积指数与冠层上层叶片的光截获率均呈显著正相关，与下层叶片的光截获率则呈负相关；籽棉产量随施氮量的减少而降低，二者有较高的相关性（R²＝0.990 5）。减氮（90～150 kg·hm^－2）增施叶面肥处理的LAI、冠层光总截获率、光透射率、冠层上下层叶片光截获率以及籽棉产量与当地常规施氮量180 kg·hm^－2处理差异均不显著。综上，旱碱地机采模式棉田增施叶面肥，对减施氮肥棉花花铃期冠层光分布、叶面积指数及籽棉产量有一定补偿作用。