8个樱花品种播种育苗技术研究

本文介绍了8个樱花品种的种子从储藏、催芽、播种到苗期管理的试验全过程,总结出一种简便易操作的樱花播种育苗技术,可供生产设施比较简陋的地方借鉴和参考。     

基于‘罗氏沼虾’养殖尾水灌溉条件下稻田养分利用效能提升技术研究

为了实现稻田消纳罗氏沼虾养殖尾水过程中水稻稳产及养分利用效率最大化,设置CK（空白对照）、BC（添加生物炭）、TG（添加土壤改良液）、BT（生物炭及土壤改良液分别减半）4个处理,依据养分运移状况及水稻生长指标的比较,筛选适宜材料类型。结果表明,BC、TG及BT的添加对表层土壤(0~10cm)TN累积、土壤(0~25cm)TP累积及养分损失,BC、TG对土壤(0~25cm)TN累积及养分损失均存在正面效应;TG显著促进表层土壤(0~10 cm)NO₃ ^-累积(P<0.05);除BC外,其他材料的养分表聚作用均促使TN、TP向根部运移(P<0.05);BT处理中灌浆期叶绿素含量显著高于TG和CK(P<0.05),材料处理组在第一节间长度均显著低于CK(P<0.05),其余处理间的差异性均未达到显著水平(P>0.05)。各处理的理论和实际产量间的差异性均未达到显著水平(P>0.05)。综上所述,相较于其他材料,有效截留NO₃ ^-为主氮素养分,提高养殖尾水养分利用率,降低淋洗污染风险;显著控制水稻底部节间生长,降低倒伏风险;且其对水稻生长及产量性状并无显著抑制作用,因而将其作为水稻消纳罗氏沼虾养殖尾水中养分利用效率提升材料具有一定应用潜力。     

推进四川兴文县竹产业高质量发展加快乡村振兴进程的思考

竹产业是兼具生态和经济效益的产业，四川省兴文县把竹产业作为振兴乡村的支柱产业进行打造，在全县各乡镇大力发展，取得了一定成效。文章在总结兴文县竹产业发展取得成效的基础上，分析了竹产业中存在的问题，对进一步推进兴文县竹产业高质量发展、加快乡村振兴进程提出了建议。     

一种新型卷积神经网络植物叶片识别方法

为提高植物叶片识别的准确率及减少计算代价,在Pytorch框架下提出一种融合了深度卷积生成式对抗网络(DCGAN)和迁移学习(TL)的新型卷积神经网络叶片识别方法。首先,对植物叶片图像进行预处理,通过DCGAN对样本数据库扩充;其次,利用迁移学习将Inception v3模型应用于图像数据处理上,以提高植物叶片识别的准确率;最后,通过对比实验对该方法的有效性进行验证。结果表明:该方法可以获得96.57%的植物叶片识别精度,同时参数训练的迭代次数由4000次缩短到560次。     

Effects of dietary Bacillus pumilus on growth performance,innate immunity and digestive enzymes of giant freshwater prawns (Macrobrachium rosenbergii)

The present study was conducted to investigate the effects of Bacillus pumilus on the growth performance, innate immunity and digestive enzymes of the giant freshwater prawn, Macrobrachium rosenbergii. Prawns (mean weight: 1.81 ± 0.01 g) were fed different levels of B. pumilus at doses of 0, 1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ CFU/g to produce one control group and three experimental groups (G1, G2 and G3), respectively. After a 60‐day experimental feeding period, the results showed that the final weight, weight gain rate (WGR) and specific growth rate (SGR) were significantly higher in experimental groups than in the control (p < 0.05), whereas these improvements did not differ significantly (p > 0.05) among experimental groups. The improvements in phagocytic activity, respiratory burst (RBs) activity and the activity of catalase (CAT), nitric oxide synthase (NOS) and acid phosphatase (ACP) were significantly higher in G2 and G3 than in the control and G1 (p < 0.05). Further, the activity of CAT, NOS and ACP significantly increased with an increase in the dietary level of B. pumilus (p < 0.05). The activity of phenoloxidase (PO) in G3 was significantly higher than that in the control (p < 0.05). The activity of amylase was significantly higher in the groups G2 and G3 than that in the control group. G3 improved the activity of protease compared with the control (p < 0.05). In conclusion, the results of this study indicated that the potential use of B. pumilusat a dose of 1 × 10⁸ CFU/g feed could improve the growth, immunity and digestive enzymes of M. rosenbergii.     

Essential amino acids supplementation to practical diets affects growth,feed utilization and glucose metabolism‐related signalling molecules of blunt snout bream (Megalobrama amblycephala)

Six diets were formulated to investigate the success of fish meal (FM) replacement by plant proteins; diet 1 reflected a commercial feed (8% FM), diet 3 contained 4% FM, and diet 5 was devoid of FM. Whereas, diet 2, diet 4, and diet 6 reflected diet 1, diet 3, diet 5, respectively, and supplemented with essential amino acid (EAA). At the end of 8‐week trial, there was no significant difference in survival rate. Significantly higher final weight, weight gain rate, and specific growth rate were recorded in the group fed diet 2 compared with the other treatments (except diet 4) (p < 0.05). Feed conversion ratio of fish fed diet 2 was significantly lower than those fed diets 1, 3, and 5 (p < 0.05). The lowest feed intake and highest protein efficiency rate were found in fish fed diet 2 (p < 0.05). There was no significant difference in whole body compositions between treatments. Plasma aspartate transaminases, alanine aminotransferase, and glucose were significantly affected by dietary treatments (p < 0.05), while plasma protein and albumin contents were not influenced by the treatments. The relative expression of target of rapamycin (TOR) and phosphatidylinositol 3‐kinase, regulatory subunit 1 (alpha) (PIK3R1) in fish fed diet 3 (4% FM) were significantly down‐regulated compared with those fed diet 6 for TOR and diets 4 and 6 for PIK3R1 (p < 0.05). Insulin receptor substrate 1 (IRS‐1) and janus kinase 3 (JAK3) expressions were fluctuated, with the higher levels in fish fed diets 4 and 6. In conclusion, the findings of this study indicate that plant protein mixture supplemented with EAA could be used to substitute FM in practical diet for Megalobrama amblycephala.     

Effects of genetically modified and non‐genetically modified soybeans with different heat treatments on growth and health of Cyprinidae species with different feeding habits

An 8‐week growth trial was conducted to investigate the effects of non‐genetically modified (nGM) soybean (Youchun 06‐1) and genetically modified (GM) soybean (Roundup Ready^®) with and without a heat treatment on the growth and health of three Cyprinidae species with different feeding habits (grass carp Ctenopharyngodon idellus, gibel carp Carassius auratus gibelio, and black carp Mylopharyngodon piceus; body weight: 283.0 ± 2.0 g, 60.5 ± 0.7 g, and 261.4 ± 3.1 g). Five diets (FM, nGMS, hnGMS, GMS, and hGMS) were made with fishmeal and full‐fat soybean (Youchun 06‐1, heat‐treated Youchun 06‐1, Roundup Ready^®, and heat‐treated Roundup Ready^®). The FM diet contained fishmeal as the sole protein source. The experimental diets contained full‐fat soybean meal as 60% of dietary protein. Both temperature (60, 80, 100, and 120°C) and duration (1 and 2 hr) of heating influenced trypsin inhibitor activity (TIA) and protein solubility of nGM soybean and GM soybean. The TIA in GM soybean was higher than that in nGM soybean. After heating at 120°C for 2 hr, each amino acid of soybean treatment showed a slight decline. Neither source of soybean nor heat treatment affected the growth performance, feed utilization, chemical composition of the whole fish body and muscle, and lipase or amylase activity of the three Cyprinidae species (p > 0.05). Heat treatment of soybean meal slightly increased the plasma antioxidant capacity of the three fish and plasma cholecystokinin of black carp and grass carp. The unheated soybean treatment adversely affected the height and density of black carp intestinal villi, and all the soybean treatments caused disruption of the grass carp intestinal epithelium.     

Genetic diversity and structure of Northern Sheatfish (Silurus soldatovi) assessed by newly developed and cross‐species microsatellites

Twenty‐five polymorphic microsatellite markers, including 13 newly isolated markers and 12 existing cross‐species markers, were used to assess the genetic variation of 141 individuals from three cultured stocks of northern sheatfish, Silurus soldatovi, in China. Samples were collected from Heilongjiang (H), Tongerpu (T) and Liaoning (L). Allelic richness, expected and observed heterozygosity among 25 loci were calculated, and the mean A_e, H_o and H_e were estimated in three stocks. In low polymorphic locus HLJcf19 and HLJcf38, most individuals in all three stocks were homozygous and had only one same allele, while only few heterozygous individuals had the other allele in one certain stock. And all the three stocks showed excess of heterozygotes, because of significant negative F_IS values. Genetic distance, UPGMA dendrogram, as well as structure analysis, all indicated that Stock H and L were closer among three stocks. The results revealed that though all stocks had no reduction in recent time, their effective population size were significantly lower to the ideal value.     

镉胁迫对烟草种子萌发和烟苗生长发育的影响

为探讨不同镉（Cd）胁迫对不同烟草品种种子萌发、幼苗生长的生理生态效应的影响,以吉烟9号、吉烟10号、延晒六号3个烟草品种为材料,研究了不同浓度的Cd溶液对烟草种子萌发以及烟苗生长发育的影响。结果表明,Cd胁迫下烟草种子发芽势、发芽率、发芽指数、活力指数、苗高均受到抑制;烟苗叶绿素含量降低,根冠比变小,生长受到抑制,CAT活性、SOD活性、可溶性糖含量随Cd浓度的增加呈先增后降的趋势,POD活性、MDA含量、Pro含量、Cd含量均随Cd浓度的增加而增加。可见Cd胁迫能不同程度地影响烟草种子萌发和烟苗生长发育,烟苗体内的抗氧化酶系统被破坏,多种酶活性不协调,生理生化过程紊乱,最终导致烟苗受害。     

农业科研副产品处置的困境及对策探讨

文章阐述了农业科研单位对科研副产品管理的现状及面临的问题,分析了农业科研副产品投入与产出的关系,并提出了以绩效考评为依据的科研副产品处置收入分配方式,从而达到优化科研人员收入分配机制的目的。