农业装备升降装置非接触式光纤位移传感器设计与试验

为了解决农业设备位移的宽量程、高灵敏度非接触测量问题,提出一种基于Peanut-shape迈克尔逊干涉结构的非接触式光纤位移传感器。分析了光纤Peanut-shape迈克尔逊干涉原理,设计了将磁场与Peanut-shape结构形成的全纤式迈克尔逊干涉相结合的传感器结构,并通过磁场仿真,得到磁场强度曲线。建立了传感器应变标定系统和位移测试系统。试验结果表明:Peanut-shape迈克尔逊干涉的光纤传感器应变灵敏度达到1. 82 pm/με,是普通光纤的1. 5倍,线性度为0. 997;位移测试得到的光谱曲线与磁场仿真曲线结果一致,可以实现位移的测量,且线性拟合度达到0. 999。     

开式离心纸浆泵叶轮流道内部流场PIV试验研究

为研究开式纸浆泵叶轮流道内纤维颗粒对液相流场的影响,采用透明有机玻璃材料制造模型样机,以清水和0.1%质量浓度的头发纤维悬浮液为介质,通过PIV试验对叶轮流道内的流动进行可视化研究.试验结果表明:当输送清水介质时,在大流量工况下叶轮流道内流动稳定,未出现旋涡和低速区;在小流量工况下,当叶轮流道旋转到蜗壳隔舌附近位置时,在叶轮流道中段压力面附近开始产生低速区,且低速区随着叶轮流道靠近隔舌位置和流量减小逐渐增大,在远离隔舌位置的叶轮流道内未产生明显的低速区;受叶片扭曲的影响,在叶轮流道内垂直于泵轴的不同截面上的相对速度大小不同,且随着叶片扭曲程度减小,相对速度差减小;输送头发纤维悬浮液介质时,在纤维颗粒的影响下,叶轮流道内的液相流动相对速度降低,导致在小流量工况下叶轮流道中段压力面附近低速区面积增大;在大流量工况下,纤维颗粒存在使液相流动的相对速度大小分布更均匀.     

Effects of planting dates and shading on carbohydrate content,yield, and fiber quality in cotton with respect to fruiting positions

Two cotton (Gossypium hirsutum L.) cultivars, Kemian 1 (cool temperature-tolerant) and Sumian 15 (cool temperature-sensitive) were used to study the effects of cool temperature on carbohydrates, yield, and fiber quality in cotton bolls located at different fruiting positions (FP). Cool temperatures were created using late planting and low light. The experiment was conducted in 2010 and 2011 using two planting dates (OPD, the optimized planting date, 25 April; LPD, the late planting date, 10 June) and two shading levels of crop relative light rate (CRLR, 100 and 60%). Compared with fruiting position 1 (FP1), cotton yield and yield components (fiber quality, leaf sucrose and starch content, and fiber cellulose) were all decreased on FP3 under all treatments. Compared with OPD-CRLR 100%, other treatments (OPD-CRLR 60%, LPD-CRLR 100%, and LPD-CRLR 60%) had significantly decreased lint yield at both FPs of both cultivars, but especially at FP3 and in Sumian 15; this decrease was mainly caused by a large decline in boll number. All fiber quality indices decreased under late planting and shading except fiber length at FP1 with OPD-CRLR 60%, and a greater reduction was observed at FP3 and in Sumian 15. Sucrose content of the subtending leaf and fiber increased under LPD compared to OPD, whereas it decreased under CRLR 60% compared to CRLR 100%, which led to decreased fiber cellulose content. Therefore, shading primarily decreased the “source” sucrose content in the subtending leaf whereas late planting diminished translocation of sucrose towards cotton fiber. Notably, as planting date was delayed and light was decreased, more carbohydrates were distributed to leaf and bolls at FP1 than those at FP3, resulting in higher yield and better fiber quality at FP1, and a higher proportion of bolls and carbohydrates allocated at FP3 of Kemian 1 compared to that of Sumian 15. In conclusion, cotton yield and fiber quality were reduced less at FP1 compared to those at FP3 under low temperature and low light conditions. Thus, reduced cotton yield and fiber quality loss can be minimized by selecting low temperature tolerant cultivars under both low temperature and light conditions.     

Nonstructural carbohydrates in leaves subtending cotton bolls,fibers and embryos in response to nitrogen stress

A field study was conducted in 2013 and 2014 where cotton was exposed to three N regimes: (1) the control without N application (low N); (2) 260 kg N ha^?1 (medium N); (3) 520 kg N ha^?1 (high N). Boll size, lint mass per boll, seed mass per boll, fiber length and strength were significantly decreased under N deprivation in the two years. The increased carbohydrate levels of LSCB (leaf subtending the cotton boll) led to decreased carbohydrate levels of fibers in the low N relative to the other N treatments. The low N embryos exhibited lower starch concentrations at 17 and 31 DPA (days post anthesis), and TNC (total nonstructural carbohydrate) concentrations at 17, 31, 45 and 52 DPA compared to medium N embryos. Starch levels in LSCB had negative associations with those in fibers at 17, 31 and 45 DPA, but positive associations with those in embryos at 24 and 45 DPA. Fibers expressed negative associations with embryos in glucose level at 24 and 38 DPA, and in TNC levels at 17 and 45 DPA. The study suggests that carbon assimilate levels in fibers and embryos could explain the difference in boll yield components and fiber quality.     

黄麻纤维产量与主要农艺性状的相关分析

研究黄麻纤维产量与主要农艺性状的相关性,可为高产育种与生产利用提供科学依据。本文159份不同来源黄麻种质资源的12个农艺性状对纤维产量即单株干皮重的影响表明,各性状的变异系数变化在11.89%至38.50%之间,表现出丰富的遗传变异。黄麻纤维产量与各性状均呈极显著正相关,其中,与单株鲜皮重、株高、始花期的相关系数较大,分别为0.814、0.760和0.648。黄麻纤维产量和单株鲜皮重、株高、出麻率、鲜皮厚的回归方程达显著水平,其标准回归系数依次为0.443、0.437、0.291和0.113。通径分析显示,单株鲜皮重、株高在决定黄麻纤维产量时起主要作用。出麻率的相关系数(0.253)与直接通径系数(0.291)表现基本一致,说明出麻率直接对黄麻纤维产量起作用,具极显著正相关。因此,在黄麻高产育种中,应该以始花期、单株鲜皮重、株高、出麻率与鲜皮厚为主要筛选对象,兼顾综合性状的改良。     

Vitrification of mouse two-cell and blastocyst stage embryos in simplified closed system using either a hemi-straw or a hollow fiber device

Two-cell stage and blastocyst stage mouse embryos were equilibrated in a medium containing 7.5% ethylene glycol (EG) and 7.5% dimethyl sulfoxide (DMSO) for 8–15 min. Vitrification was performed in a medium containing 0.5 M sucrose and either 15% EG + 15% DMSO, 17.5% EG + 17.5% DMSO, or 20% EG + 20% DMSO for 30 s. They were then placed either on a hemi-straw (HS) or a hollow fiber vitrification (HFV) device and vitrified by cooled air inside a 0.5-ml straw. In two-cell embryos, a 100% survival rate was obtained from all groups except the 20% HS group (P > .05). All vitrified two-cell groups showed similar rates of blastocyst development to that of fresh control group (P > .05), except 17.5% and 20% HFV groups, which were significantly lower than the other groups (P < .05). In the blastocyst embryos, the HFV groups were divided into two subgroups (non-collapsed; HFV-NC and collapsed; HFV-C blastocyst). Re-expansion rate in 15% HFV-NC, 17.5% HFV-NC, and 15% HFV-C groups was reduced (P < .05), whereas the rest were similar to control. In conclusion, we established a simplified, reliable, and closed system for HFV vitrification applying hemi-straw, which does not require skilled practitioners.     

Agronomic traits at the seedling stage,yield, and fiber quality in two cotton (Gossypium hirsutum L.) cultivars in response to phosphorus deficiency

ABSTRACT

Cotton is critical for phosphorus demands and very sensitive for its deficiency. However, identifying the effect of low-phosphorus tolerance on cotton growth, yield, and fiber quality by reducing phosphorus consumption. This may help to develop phosphorus-tolerant high-yielding cotton cultivars. In a two-year repeated (2015 and 2016) hydroponic experiment (using 0.01 and 1 mM KH₂PO₄), two cotton cultivars with phosphorus sensitivity (Lu 54; a low-phosphorus sensitive and Yuzaomian 9110; a low-phosphorus tolerant) were screened on the base of agronomic traits and physiological indices through correlation analysis, cluster analysis and principal component analysis from 16 cotton cultivars. Low phosphorus nutrition reduced the plant height, leaf number, leaf area, phosphorus accumulation and biomass in various organs of seedlings. The deficiency negatively affected the morphogenesis of seedlings, as well as yield and fiber quality. Further, these screened cultivars were tested in a pot experiment with 0, 50, 100, 150, 200 kg P₂O₅ ha^?1 during 2016 and 2017. It was found to have a significant (P< 0.05) difference in boll number, lint yield, fiber strength, and micronaire at the harvest. Furthermore, after collectively analyzed the characteristics of Lu 54 and Yuzaomian 9110, there were six key indices that could improve the low phosphorus tolerance of cotton cultivars. These were root phosphorus accumulation, stem phosphorus accumulation percentage, leaf and total biomass of seedlings, seed cotton weight per boll and fiber length.     

施氮量对油后直播棉花产量、品质及生物量的影响

为研究施氮量对油后直播棉花生物量累积特征及其与产量、品质的关系,于2016-2017年在湖南常德设置了施氮量分别为0、90、180、270、360 kg·hm^-2氮肥水平试验。结果表明,在施氮量为0~360 kg·hm^-2范围内,施氮量越大棉株营养器官生物量累积越多,而棉株生殖器官生物量则在施氮量为270 kg·hm^-2时累积最多;皮棉产量、成铃数和单铃重均在施氮量为270 kg·hm^-2时达到最大;0~270 kg·hm^-2范围内,衣分随施氮量增加而增加。在施氮量为270 kg·hm^-2条件下,纤维长度和断裂比强度最高;适宜施氮量有利于纤维长度、断裂比强度的提高和马克隆值的优化,对伸长率和整齐度基本无影响。综上所述,适宜施氮量可提高棉花的产量、品质,洞庭湖棉区适宜的施氮量为180~250 kg·hm^-2。本研究结果为环洞庭湖棉区的氮肥合理运筹提供了技术参考。