Hydraulic Resistance of Sorghum (C4) and Sunflower (C3)

Summary

It is well known that C4 crops have a lower water requirement than C3 crops. Reasons for the difference are not well understood. Therefore, hydraulic resistance of sorghum [Sorghum bicolor (L.) Moench] (C4) and sunflower (Helianthus annuus L.) (C3) was determined to see if it might be one explanation for the lower water use of crops with the C4 photosynthetic pathway. Plants were grown under greenhouse conditions in pots with soil, which was well watered (soil matric potential of ～0 MPa) or allowed to dry (soil matric potential of ?0.038 MPa and ?0.065 MPa for sorghum and sunflower, respectively). Hydraulic resistance was calculated in two ways: (1) using the classic Ohm's law analogue, which assumes that the relation between flux (transpiration) and difference in water potentials of the soil and plant is linear and (2) using an equation that considers diurnal changes in leaf water content along with transpiration and difference in water potentials. Because change in leaf-water content during a day was small, hydraulic resistances calculated by the two methods resulted in similar values. Sorghum had a linear relationship between flux and difference in potentials (constant hydraulic resistance), but sunflower had a nonlinear one (variable hydraulic resistance). The hydraulic resistance of watered sunflower increased only slightly during a day and averaged about 40 MPa m² s mol^?1, which was 3.5 times less than that of watered or water-stressed sorghum (-140 MPa m² s mol^?1). The hydraulic resistance of water-stressed sunflower increased steeply during a day and by the end of the day it had a hydraulic resistance that approached that of sorghum.     

基于因素空间的油葵联合收获机故障诊断推理机制

当油葵联合收获机出现脱粒滚筒堵塞等故障时会影响联合收割机作业效率,而缺少自动故障早期预警手段的问题日益突出。为此,以因素空间理论为基础,研究了油葵联合收获机的故障诊断问题。在因素空间中,油葵联合收获机故障通过将其征兆因素集综合起来进行描述,通过因素分析得到故障诊断类型;并构建了装备故障诊断知识库和推理机制,进行了油葵联合收获机故障诊断仿真。仿真结果表明:基于因素空间理论的故障诊断方法能够成功地诊断出其故障类型,对油葵作物联合收获机的科学维护及可靠运行提供重要的参考。     

内蒙古河套灌区食用向日葵肥料对比试验

[目的]开展内蒙古河套灌区食用向日葵肥料对比试验。[方法]以河套灌区市场内主要流通的6个肥料产品为研究材料,通过与该地区传统施肥模式(CK)进行对比,分析了不同肥料对食用向日葵产量、效益的影响。[结果]525 kg/hm~2田力元掺混肥(17-17-17)+375 kg/hm~2尿素、450 kg/hm~2住商缓释肥(24-12-10)、450 kg/hm~2德源缓释肥(24-12-10)的增产效果显著,较对照(CK)分别增产13.3%、11.9%和5.6%;525 kg/hm~2田力元掺混肥(17-17-17)+375 kg/hm~2尿素、450 kg/hm~2住商缓释肥(24-12-10)、450 kg/hm~2德源缓释肥(24-12-10)、450 kg/hm~2奥佳缓释肥(26-10-12)的效益显著,较对照(CK)分别增收12.3%、11.5%、7.5%和5.0%。[结论]该研究可为当地向日葵生产提供科学理论依据。     

Interspecific hybridization between sunflower and wild perennial Helianthus species via embryo rescue

Interspecific crosses were made between the cultivated sunflower inbred line HA89 and accessions of five wild perennial Helianthus species (H. giganteus L., H. laevigatus T. & G., H. resinosus Small, H. pauciflorus Nutt. and H. decapetalus L.) resistant to broomrape ( Orobanche cernua Loefl.). Using the genetic male-sterile isogenic version of that line as female, successful reciprocal crosses were also obtained with all these wild species except with H. decapetalus. Five-day-old hybrid embryos were excised and cultured in vitro. In all cases, few mature plants were obtained from embryos in early developmental stages (early heart and globular) but up to 28% mature plants were obtained from embryos in later stages of development. Very immature embryos were difficult to excise without damage. Hybrid embryos and mature plants were obtained from all five wild species. Interspecific hybrid embryos from different wild species showed distinct developmental potentials, the proportion of hybrid embryos in different developmental stages varying among species. Differences in the proportion of hybrid embryos at the several developmental stages were also obtained for the reciprocal crosses (cultivated × wild), which showed higher proportion of fully developed embryos. Hybrids involving H. giganteus and cultivated sunflower were difficult to obtain without the use of embryo culture. Embryo culture proved to be an useful tool to overcome post-zygotic hybrid incompatibility in different Helianthus spp., and facilitated interspecific transfer of resistance to O. cernua. This revised version was published online in July 2006 with corrections to the Cover Date.     

不同类型向日葵籽粒的理化性质

为明确不同类型向日葵籽粒理化性质与利用价值,以3种不同类型向日葵籽仁为研究对象,检测其粗蛋白质、粗脂肪、氨基酸、微量元素、维生素E和植物甾醇含量,脂肪酸组成以及抗氧化活性.研究表明,观赏向日葵阿尔卑斯橙子红晕黑心和食用向日葵JZ055粗脂肪含量分别为44.55％和41.26％,低于油用向日葵陇葵杂6号(49.93％),...     

一种快速检测向日葵地块土壤中黄萎病菌微菌核的新方法

由大丽轮枝孢菌侵染引起的向日葵黄萎病是一种重要的土传病害,微菌核是该病害主要的初侵染来源。目前,土壤中大丽轮枝孢菌微菌核的定量检测方法多操作步骤复杂繁琐,如利用PCR方法进行检测,对仪器设备和操作人员的素质都有较高的要求,而常规的土壤梯度稀释湿筛法的实验周期长且检测效率低,因此,建立一种快速定量检测土壤中大丽轮枝孢菌微菌核的方法,对于向日葵黄萎病的预报预测和防控非常重要。为了能够快速的定量检测土壤中微菌核的数量,以期探明不同耕作方式地块中土壤微菌核数量的差异,本实验建立了一套操作相对简单,实验周期较短的微菌核快速分离和定量检测的方法,即采样器—干筛法。该方法将微生物采样器和选择性培养基相结合,基于微生物采样器的撞击法原理,使土壤微生物粒子加速撞击到选择性培养基的培养皿表面,经培养后可见单菌落形成。利用该方法对内蒙古巴彦淖尔市不同的向日葵黄萎病发病地块中采集到的土壤样本中微菌核进行了定量检测,结果表明：两年向日葵连作地（样地1）土壤中微菌核的数量最多,平均每克土样中含有微菌核32.80个;与非寄主作物玉米轮作地块（样地2）土样中微菌核的数量最少,平均每克土样中含有微菌核11.80个,与寄主作物打籽葫芦轮作地块（样地3）微菌核数量介于二者之间。利用该方法能够明显区分不同地块土壤中微菌核的数量。通过和荧光定量PCR检测的结果进行相关性分析发现,该方法能够准确检测土壤中大丽轮枝孢菌微菌核的数量。     

Growth and economic analysis of freshwater prawn,Macrobrachium rosenbergii (de Man), produced with feeds substituting sunflower cake for fish meal,soya bean meal and mustard oil cake

A feeding trial with Macrobrachium rosenbergii was carried out to test the effectiveness of sunflower cake (SFC) as a replacement for conventional protein sources. Four isonitrogenous (~30% crude protein) and isocaloric (388–402 kcal) diets were formulated. Diet‐1 was a control made with conventional ingredients including fish meal, soya bean meal and mustard oil cake. Diet‐2, Diet‐3 and Diet‐4 were made with 30%, 40% and 50% SFC, respectively, replacing the usual protein sources used in Diet‐1. After 100 days, diets with SFC inclusion showed favourable growth and economic performance trends compared to control diet‐1, but without significant differences (p > .05). Better production (572.89 ± 62.99 kg/ha) was observed with Diet‐4 followed by Diet‐2, Diet‐3 and Diet‐1. Diet‐4 revealed the best feed conversion ratio (2.56 ± 0.24), specific growth rate (1.18 ± 0.05) and protein efficiency ratio (1.14 ± 0.10) among these diets. Whole carcass composition analysis revealed highest crude protein (18.19%) and lipid (4.43%) content in prawns fed Diet‐3 followed by Diet‐4. Highest total income, gross margin and benefit cost ratio (BCR) per hectare from prawns were US$5,759, US$2,623 and 1.84, respectively, found in Diet‐4. This study demonstrates that 30%–50% inclusion of SFC has favourable impacts on productivity and profitability compared with controls, with 50% SFC inclusion as the most cost‐effective diet for prawns without apparent compromise in growth, flesh quality or economics. The performances of the diets suggest that SFC may be a suitable substitute for fishmeal, soya bean meal and mustard oil cake in prawn feed. The effectiveness of higher SFC concentrations should also be investigated.     

盐渍化土壤向日葵水-肥耦合试验研究

以内蒙古河套灌区主要作物油料向日葵为研究对象,进行了田间试验,采用312-D最优饱和试验设计方案,随机排列,2次重复,以产量为目标函数建立了不同盐分水平下的回归模型,并进行分析。研究结果表明,在盐渍化地区土壤中水肥因子的影响效应轻度盐渍化土壤依次为水分、磷、氮,中度盐渍化土壤依次为水分、氮、磷。最佳水肥配比范围轻度灌水量为1 581～2 116 m3/hm2,中度灌水量为1 088～1 549 m3/hm2,氮为225 kg/hm2,磷为150 kg/hm2。     

Exogenous xylanase improves growth,protein digestibility and digestive enzymes activities in Nile tilapia,Oreochromis niloticus,fed different ratios of fish meal to sunflower meal

A 3 × 2 factorial experiment was designed to evaluate the effect of different ratios of fish meal (FM): sunflower meal (SFM) with or without exogenous xylanase supplementation on growth, feed utilization, digestive enzymes activities, apparent digestibility, intestinal and liver morphology and chemical composition of Nile tilapia, Oreochromis niloticus. Three isonitrogenous (329.80 g/kg of crude protein) and isoenergetic (18.46 MJ/kg gross energy) experimental diets were formulated as SFM₁ (FM:SFM = 2:1), SFM₂ (FM:SFM = 1:1) and SFM₃ (FM:SFM = 1:2) based on protein content. Each diet was supplemented with 0 or 0.5 g/kg of exogenous xylanase and was fed to triplicate groups of twelve fish (with initial weight, 1.31 ± 0.02 g) for 84 days. After 84 days of feeding period, the highest weight gain, specific growth rate, protein efficiency, protein productive value and the best feed conversion ratio were recorded in fish fed either SFM₁ or SFM₂ supplemented with exogenous xylanase. Whereas lowest growth performance was recorded in fish fed SFM₂ and SFM₃ un‐supplemented with xylanase. The highest activities of chymotrypsin, trypsin, lipase, amylase, alkaline phosphatase and cholecystokinin were observed in fish fed SFM₁ and SFM₂ diets supplemented with xylanase. The highest ADCs of dry matter, protein, lipid and digestible energy were recorded in fish fed SFM₁ and SFM₂ diets supplemented with exogenous xylanase. Supplementation of exogenous xylanase improved muscularis mucosa thickness, height of mucosal folds and enterocytes of intestinal fish. Addition of exogenous xylanase increased the calcium and phosphorus retention. Results of this study indicated that the addition of exogenous xylanase to diet containing high inclusion level of sunflower meal improved growth, digestive enzymes, nutrient digestibility, histological morphometric of liver and intestine and nutrient retention.