Effects of Seed Rate on Root Twining Power and Seedling Quality of Machine-transplanted Super Rice

In order to investigate the effects of seed rate on root twining power and seedling quality of machine-transplanted super rice cultivars, Yongyou 12 and Zhongzheyou No.l, total 6 seed rates were arranged, and the growth characteris- tics, quality and root twining power of machine-transplanted rice seedlings were studied. The results showed that seed rate had great effects on root twining power and qualityof rice seedlings; with the increase of seed rate, the root twining power of rice seedlings was increased, but the quality of rice seedlings was significantly reduced; under the condition of high seed rate, rice seedlings were weak with less accumulate dry matter and nonuniform growth, and the proportion of weak seedlings was higher. When the seed rate of both rice cultivars was reduced by 10 g/tray, the average seedling height was increased by 0.5 cm, leaf age was increased by 0.1, stem base diameter was increased by 0.1 cm, and root number per plant was increased by 0.3. When the seed rate was increased by 10 g/tray, the accumulated dry matter per plant was reduced by 5.1 mg. With the increase of seed rate, the seedling quality of Zhongzheyou No.1 was decreased rapidly, and the proportion of weak seedlings was increased rapidly. However, Yongyou 12 has a larger elasticity in seed rate. When the seed rate reached to 50 g/tray, blanket seedlings of Yongy- ou 12 were nursed with uniform growth and higher quality, but the shoots were sparse with lower leaf area index. However, when the seed rate was up to 50 g/tray, blanket seedlings of Zhongzheyou No.1 were nursed with uniform growth and higher quality, as well as higher-density shoots. From a comprehensive point of view, the optimum seed rates of Yongyou 12 and Zhongzheyou No.1 were 65 and 50 g/tray, respectively.

Effects of Mechanized Transplanting and Fertilization Mode on Population Growth and Development of Male Parent in Seed Production of Hybrid Rice

In order to study the effects of mechanized transplanting and fertilization mode on population growth and development of the male parent in seed production of hybrid rice, three male parents, Huazhan, Shuhui 527 and R9311 were selected as materials. The male parents were transplanted by rice transplanter with two kinds of line spacing design, six lines with equal row spacing （20/25 cm x 30 cm） and wide and narrow spacing （20/25 cm x 40, 20 cm）, and artificial transplanting with equal row spacing （20/25 cm x 30 cm） was set as the control. The three fer- tilization modes were applying for one, two and three times. The flowering stage and panicle-spikelet structure of the male parent were investigated. The results showed that the effects of mechanized transplanting and fertilization mode were little on the duration from seeding to heading; the panicles and spikelets of the three male parents were significantly increased by mechanized transplanting. The tiller number was increased by mechanized transplanting and fertilizing for two and three times. Wide and narrow spacing by machine planting and fertilizing for three times were suitable for Huazhan, which significantly increased the number of spikelets per unit area. Furthermore, the number of spikelets per unit area of Shuhui 527 and R9311 were significantly increased by mechanized transplanting and fertilizing for three times.

Genotypic Differences in Growth and Physiological Responses to Transplanting and Direct Seeding Cultivation in Rice

The field experiments were conducted to investigate the growth and physiological responses of six super hybrid rice combinations to two planting methods, transplanting （TP） and direct seeding （DS） during 2006-2007 and 2007-2008. The 1000-grain weight and number of tillers per plant at the early growth stage, the maximum quantum yield of PSII （Fv/Fm） and transpiration rate （Tr） were higher in DS plants than in TP ones, whereas the grain yield, number of panicles per square meter, seed setting rate, net photosynthetic rate （Po） and stomatal conductance were lower in DS plants. However, little difference was detected in number of grains per panicle, stem （shoot） and leaf weight between the combinations in the two planting methods. The responses of plant growth and physiological traits to planting method differed greatly among the six combinations. In both planting methods, Chouyou 58 and Yongyou 6 had the highest and lowest panicle biomass and Pn, respectively. The higher yield of Chunyou 58 was associated with more numbers of panicles per square meter and grains per panicle in both planting methods. The results indicate that lower grain yield in DS relative to TP is attributed to more excessive tillers at the early stage, lower leaf biomass and photosynthetic rate at the late stage.

Correlation of Leaf and Root Senescence During Ripening in Dry Seeded and Transplanted Rice

Dry seeding is a resource-saving rice establishment method. With an equivalent yield, dry seeded flooded rice （DSR） has been considered as a replacement for traditional transplanted flooded rice （TFR）. However, the differences in leaf and root senescence during grain filling between DSR and TFR were seldom identified. In this study, the root length, root tip number and leaf senescence of rice varieties Huanghuazhan and Yangliangyou 6 during ripening were compared between DSR and TFR. Results showed that top three leaves in DSR had the characteristics of relatively lower SPAD value, lower N content and premature leaf senescence. In addition, both the total root length and total root tip number of DSR were significantly lower than those of TFR. In conclusion, premature and quick leaf senescence was related with inadequate root length and root tip number during ripening, which might result from the deficiency of nitrogen supply in DSR. Techniques on improving leaf nitrogen status and delaying the leaf senescence during grain-filling in DSR should be developed in future researches.

Living donor liver transplantation with abdominal wall reconstruction for hepatocellular carcinoma with needle track seeding

Malignant cell seeding in subcutaneous tissues along the needle track and/or percutaneous biliary drainage catheters is rare complication, but pose various technical issues in planning surgical treatment of such patients. If underlying primary hepatic malignancy can be treated, an aggressive resection of subcutaneous tissue bearing cancer cell with subsequent abdominal wall reconstruction has been sporadically reported. But, when hepatic resection is not possible due to underlying advanced cirrhosis, liver transplantation along with abdominal wall resection and subsequent reconstruction remains only feasible option. Herein, we describe our successful experience of living donor liver transplantation for hepatocellular carcinoma with fullthickness abdominal wall resection bearing the tumor seeding followed by reconstruction in single stage surgery.

Influence of Date of Transplanting on Growth and Yield Attributes and Resultant Seed Quality of Davana

A field experiment was conducted at TamilNadu agricultural university, Coimbatore during rabi 2011 to study the effect of time transplanting on growth, yield attributes and resultant seed quality of davana. The experiment was laid out with five different dates of transplanting viz., October 15th, November 1st, November 15th, December 1st and December 15th with the spacing of 15 × 7.5 cm and 125:125:75 NPK kg/ha were adopted in a randomized block design with four replications. The results revealed that the seedlings transplanted at 15th November recorded the maximum number of branches/plant, seed yield/plant, seed yield/plot, resultant seed germination and vigour index.

Contrast Test Between Direct Seeding and Seedling Transplanting of Diwangcai

To improve the yield of Diwangcai and explore its best cultivation way,direct seeding and seedling transplanting of Diwangcai were contrasted. The results showed that cumulative annual yield of Diwangcai by seedling transplanting was 16% higher than that by direct seeding.

Temporal Dynamics of Antioxidant Defence System in Relation to Polyamine Catabolism in Rice under Direct-Seeded and Transplanted Conditions

Six rice cultivars viz. PR120, PR116, Feng Ai Zan, PR115, PAU201 and Punjab Mehak 1 under the direct-seeded and transplanted conditions were used to investigate the involvement of antioxidative defence system in relation to polyamine catabolism in temporal regulation of developing grains. Activities of ascorbate peroxidase （APx）, guaiacol peroxidase （GPx）, catalase （CAT）, superoxide dismutase （SOD）, polyamine oxidases （PAO） and contents of ascorbate, a-tocopherol, proline and polyamines increased gradually until mid-milky stage and then declined towards maturity stage under both planting conditions. The transplanted condition led to higher activities of antioxidative enzymes （APx, GPx and CAT） and contents of ascorbate, a-tocopherol and proline whereas the direct-seeded condition had elevated levels of PAO and SOD activities and contents of polyamines, lipid peroxide and hydrogen peroxide. Cultivars Feng Ai Zan and PR120 exhibited superior tolerance over other cultivars by accumulating higher contents of ascorbate, a-tocopherol and proline with increasing level of PAO and SOD activities under the direct-seeded condition. However, under the transplanted condition PR116 and PAU201 showed higher activities of antioxidative enzymes with decreasing content of lipid peroxide. Therefore, we concluded that under the direct-seeded condition, enhancements of polyamines content and PAO activity enabled rice cultivars more tolerant to oxidative stress, while under the transplanted condition, antioxidative defence with decreasing of lipid peroxide content was closely associated with the protection of grains by maintaining membrane integrity during rice grain filling. The results indicated that temporal dynamics of H2O2 metabolic machinery was strongly up-regulated especially at the mid-milky stage.

轻简化栽培稻田杂草发生趋势与防控技术

随着水稻轻简化栽培技术的应用与推广,东北稻区、西北稻区、长江流域稻区和华南稻区等水稻主产区的杂草种群演替加快,稗草、千金子和马唐等恶性杂草频繁发生,杂草抗药性水平上升迅速。若杂草防控不及时、不彻底,极易对水稻生产构成严重威胁。为此,对水稻直播、机插和抛秧等轻简化栽培稻田杂草的草相特征、发展趋势和防除方法等进行了概述,以期为制定合理、高效的轻简化栽培稻田杂草综合防控技术、水稻用农药减量增效除草方案,延缓杂草抗药性产生与发展提供借鉴。

水稻无人机直播产量、效益分析及技术要点

以常规水稻品种秀水14为供试品种,比较了机械插秧、行走式机械直播和无人机直播3种种植方式的产量、成本和效益,分析了不同种植方式的工作效率与群体均匀性。结果表明,无人机直播的产量与机械插秧、行走式机械直播无显著差异,但其具有播种效率高、群体生长均衡、种植成本低的特点。最后小结了无人机直播技术要点。

烟苗移栽机用浇水装置的设计与试验

针对现有烟苗移栽机用浇水装置水资源利用率不高、浇水时会对幼苗和土壤造成强烈冲击以及不能够与移栽作业保持同步运行等问题,提出了一种新的烟苗移栽机用浇水装置。通过建立该装置的三维模型并对其中的倒水组件进行了理论研究和ADAMS仿真,得到了其运动特性及运动曲线图。首先,以时间作为试验指标,通过浇水组件对不同体积的水进行浇灌试验,测量所需的倒水时间和总时间,并对其进行一元线性回归拟合得到拟合方程;其次,采用相同体积的水,利用不同出水口口径的导流器进行浇灌试验并进行单因素方差分析。结果表明:导流器出水口口径的大小是影响浇水时间的重要因素,口径越大,导流速度越快,浇水所需时间越短。将装置设置于移栽机上,可与移栽作业保持同步。研究为移栽机用浇水装置提供了一种新的设计思路和理论依据。

血管化类器官的构建策略

背景:有效促进类器官内部血管发生是目前类器官培养中的焦点问题,作为一种新近发展的生物培养技术,血管化的类器官在研究活体组织的发育、疾病形成的机制、组织替代疗法以及药物筛选等方面,都有很大的研究和应用价值。目的:对近年来类器官血管化的方法或策略进行归纳总结,分析类器官血管化形成机制以及构建策略,以期为更加深入地研究类器官的发生机制和为临床转化提供可靠的思路。方法:检索PubMed及中国知网数据库收录的相关文献。英文检索词为“organoids,Vascularization,Vascular,Vascular development,vessel”,中文检索词为“血管发生,血管生成,类器官,干细胞,血管化,预血管化”,最终纳入77篇文献进行归纳总结。结果与结论:①类器官血管化形成机制涉及3个关键因素,即种子细胞、细胞因子与细胞外基质。种子细胞为血管化类器官提供了关键的细胞来源,细胞因子为类器官内部的血管发生起了重要的信号引导作用,细胞外基质为血管细胞提供了外在的生长环境,促进类器官血管化的发生。②血管化类器官的构建策略包括细胞自我重组、微血管碎片渗入、宿主体内移植以及微流控芯片等。体外诱导多能干细胞向血管内皮祖细胞分化能顺利与邻近组织整合并具有血管生成的潜力,故可利用多能干细胞的自我重组功能构建血管化类器官。微血管碎片保留了其细胞复杂性、天然结构和表型可塑性,更利于模拟天然微血管从而促进类器官的血管化。宿主体内移植是目前类器官实现完整血液灌流的最佳方法,而微流控芯片则为实现类器官体外血液供应提供了解决方案。③类器官的多种构建策略如多类干细胞共分化、信号分子的精准调控、微血管渗入和活体宿主移植等,一定程度上在类器官中引入血管成分,使得类器官在功能和成熟度上更接近相应组织。然而缺乏血流灌注仍然是一个难题,迄今为止,仅宿主体内移植才能在类器官中实现有效的血流灌注,因此类器官在血管化方面仍面临许多挑战。

伸缩取栽式水稻钵苗移栽机构设计与试验

针对现有夹苗式水稻钵苗移栽机构在取苗时因穴盘中秧苗长度、位置、粗细以及每穴成苗量不一致使得夹苗部位存在差异而导致秧苗直立度降低的问题,设计了一种伸缩取栽式水稻钵苗移栽机构。该机构在到达植苗点推秧时,秧苗土钵相对泥面的上下栽植运动会优先于水平相对运动,保证了秧苗土钵入土的直立性。对该机构开展了目标轨迹设计和结构设计,对非圆齿轮行星轮系和栽植臂伸缩机构进行了运动学分析,结合水稻钵苗移栽的农艺要求确定了优化目标,建立了优化目标数学模型,开发了参数优化辅助设计软件;分析了不同机构参数对移栽轨迹的影响,并通过人机交互的方式得到了一组满足移栽机构工作要求的机构参数。开展了仿真试验和实物样机移栽试验,结果表明:实物样机轨迹、仿真轨迹和理论轨迹基本一致,且试验测量参数与理论参数误差均在2.5%内。该研究提出的伸缩取栽式水稻钵苗移栽机构,降低了泥面对被栽秧苗的水平折弯现象,大幅提高了秧苗的直立度,为水稻钵苗移栽机构在提升秧苗直立度方面的研发提供一种新思路,也可为夹苗式水稻钵苗移栽机的后续研究提供借鉴。

肝脏类器官在肝脏疾病模型与移植治疗中的应用潜力

背景:肝脏类器官对阐明肝脏疾病的确切病理机制及对肝脏疾病的治疗具有重要的意义。目的:总结目前国内外该领域的基础研究,回顾以往肝脏类器官的构建、疾病建模和移植治疗的重要研究进展,探讨肝脏类器官联合组织工程技术的应用前景。方法:检索PubMed数据库及中国知网数据库收录的相关文献,英文检索词为“liver,organoids,liver diseases”,中文检索词为“肝,类器官,肝脏疾病”,主要检索时限为2018年4月至2024年4月,通过人工阅读排除重复文献等,最终纳入94篇文献进行归纳分析。结果与结论:①肝脏类器官构建的种子细胞主要集中于成体细胞和多能干细胞,通过辅助各种细胞因子参与信号引导作用和细胞外基质提供3D微环境,促进类器官的产生,但是整体成熟度不高,有望通过结合组织工程技术改善这一问题;②体外疾病建模方面主要在简单疾病和单基因遗传病领域研究较多,类器官高度保留患者遗传特性,有望通过结合CRISPR-Cas9基因矫正和其他新兴技术模拟更复杂的肝脏疾病并阐明更深层次的病理机制;③体内移植治疗方面,肝脏类器官能够安全有效的植入,表现出惊人的肝功能替代潜力及组织再生能力,并且还可能通过与其他组织工程材料结合达到治疗目的。

不同栽培方式和灌溉模式对水稻生长特性、产量和水分利用效率的影响

旨在探讨不同栽培方式下灌溉模式对水稻生长特性、产量和水分利用效率的影响,并阐明机理。选取“Y两优1928”为供试稻种开展水稻种植的测坑试验,设置2种栽培方式:移栽(C1)和直播(C2),3种灌溉模式:淹水灌溉(W1)、间歇灌溉(W2)和蓄雨型间歇灌溉(W3)。结果表明,C2全生育期茎蘖数和茎蘖成穗率均高于C1,W2、W3有利于抑制水稻前期无效分蘖和保持黄熟期有效茎蘖数;C2叶面积指数显著高于C1,W2、W3有利于减缓叶面积指数的下降。C2产量较C1平均提高1.92%,W2、W3产量较W1平均提高11.47%、10.54%。W2、W3水分利用效率较W1平均提高了35.5%、40.72%;W3全生育期灌水量较W2、W1减少了66.06%、19.80%,降雨利用率较W2、W1平均提高了30.66%、26.28%。直播栽培结合蓄雨型间歇灌溉可以协同提高水稻产量,减少灌水量,提高水分利用效率和降雨利用率,实现水稻高产和水分高效利用。

甘薯脱毒及种薯(苗)繁育技术研究

中国是世界上最大的甘薯生产国,然而由于病毒病的存在,严重制约了甘薯产业的发展,建立通用的脱毒组培体系、高灵敏度的检测体系及高效的种薯(苗)繁育体系对甘薯产业发展具有重要意义。对12个主栽品种进行茎尖脱毒处理,建立了通用的脱毒组培体系MS+2 mg/L NAA+1.0 mg/L 6-BA,大多数品种的再生率在58%以上;获得SPFMV、SPCSV、SPLV、SPCFV和SPVG这5种病毒的特异性引物,该引物对病毒检测极限依次为10^(-6)、10^(-1)、10^(-4)、10^(-3)和10^(-3),具有较高的灵敏性;对脱毒品系进行筛选,获得优良脱毒株系甘12和粉薯2-2;建立脱毒种薯(苗)的三级繁育体系,即组培苗(一级)扩繁,温网室基质苗(二级)扦插扩繁和网棚大田苗(三级)繁育生产用种;进行洗苗速率(带根和不带根)对比试验,移栽方式(带根和不带根)与每孔移栽棵数(1~3棵)的双因素试验,结果表明不带根处理可显著提升洗苗速率,育苗前期每孔移栽棵数(1~3棵)在株高、茎粗、节间数方面无显著差异,带根处理前期生长具有优势,但二者成活率无显著差异,并不影响育苗结果。因此,该研究有利于甘薯病毒病防治、脱毒种薯(苗)推广和育苗成本的降低。

组织工程角膜内皮移植研究进展

由于角膜供体材料严重短缺,穿透角膜移植术及角膜内皮移植术的临床广泛开展受到严重制约,其根本原因在于健康角膜内皮的增生能力有限。随着组织工程技术和细胞工程技术不断发展,组织工程角膜研究已取得一定进展,应用组织工程技术体外培养高密度、具备健康内皮功能的角膜内皮细胞进行移植是当前研究的热点。组织工程角膜内皮技术研发的关键在于种子细胞、载体材料和移植方式的选择。目前,国内外大量研究的种子细胞来源包括人角膜内皮细胞、干细胞、血管内皮细胞及人羊膜上皮细胞等。常见的载体材料包括羊膜、脱细胞角膜基质、后弹力层、晶状体前囊膜等。体外培养的细胞采用穿透角膜移植术、角膜内皮移植术或前房注射细胞的方式进行移植。本文从角膜内皮种子细胞来源、移植载体选择以及角膜内皮移植方法等方面就组织工程角膜内皮移植研究进展进行综述,总结目前研究面临的问题并展望其前景。

宣粳糯7号选育及作麦茬稻种植的高产栽培技术

本文分析了宣粳糯7号的选育过程及其特征特性,并从机插秧和直播两种栽培模式总结其作为麦茬稻的高产栽培技术。选育方面宣粳糯7号是以宣粳糯1号为母本,粳糯86120-5为父本经过系统选育而成的早熟晚粳糯稻品种,具有耐迟播、抗逆性强和适应性广等品种特性,适宜机插秧和直播作麦茬稻种植。作麦茬稻高产栽培技术原则是在有足够的有效穗数基础上,促壮秆、成大穗和增粒重,配合病虫草害防治。具体措施包括适时适量播种、科学肥水管理、综合防治病虫草害和适时收获等,机插秧还要求匀栽密植、插足基本苗。目的在于为该品种的推广种植提供参考。

不同栽培基质对船盔乌头组培苗移栽及种子萌发效果的影响

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