中国北方5种下垫面对沙尘暴的影响研究

利用中国北方农田、草地、沙地、戈壁、盐壳5种不同下垫面15个气象站点40年的大风与沙尘暴日数气象数据，对这5种下垫面大风日数与沙尘暴日数之间的关系进行了定量研究。通过分析初步得出：大风日数与沙尘暴日数之间存在着一定的相关关系。下垫面对沙尘暴有重要的影响，不同下垫面的沙尘暴日数存在着较大的差异。草地、戈壁、盐壳的沙尘暴日数明显少于大风日数，沙尘暴日数的年际变化较小，农田与沙地的沙尘暴日数明显增多，甚至在许多年份中多于大风日数。这种差异是由不同下垫面对沙尘暴的影响机制决定的。     

早稻磷肥残效对当年晚稻产量的影响

通过2年的大田实验，研究了早稻磷肥施用量0、30、60、90、120、150kg hm^-2（以P2O5计）6个水平下的残效效应，分析了晚稻有效穗数、穗粒数、结实率和千粒重等产量构成因素及水稻实际产量与磷肥残效水平之间的相关性。结果表明：磷肥残效主要通过有效穗数和穗粒数影响晚稻产量。晚稻增产百分率随着早稻磷肥施用量的增加而增加。由于年际之间气候条件（主要是干旱因素）的分异，磷肥残效对晚稻增产效果在不同年际之间表现出较明显的差异；磷肥对提高晚稻抗旱能力有一定的作用。同时早稻磷肥施用量应该控制在P2晚为85～135kg hm^-2的范围。     

锌肥对作物产量、子粒锌及土壤有效锌含量的后效

1992年一1998年在河南新乡缺锌褐土进行了微区定位试验，研究施锌对作物和土壤的长期效应。结果表明：施锌提高第一茬作物小麦的分蘖数、穗数、穗长和第二茬作物玉米的穗长、穗粒数和粒重，从而显著增加小麦和玉米产量。不同用量的锌对作物产量影响末及显著差异水平。施锌对作物产量的后效不明显，最多能维持两茬作物。施锌显著提高土壤有效锌含量，尽管施用锌肥，经过4茬之后，土壤有效锌含量仍维持在临界值之上，但作物产量没有多大影响。施锌显著提高前2茬小麦和前3茬玉米子粒中锌含量。     

牛体外胚胎质量检测与评价

来源于体外成熟和体外受精的牛早期胚胎与不同细胞的单层细胞共同培养，以检测不同阶段胚胎的细胞数。本研究共检测了３１５３枚桑椹胚和囊胚。通过体外培养４～１０ｄ，不同阶段的胚胎，早期桑椹胚、紧凑型桑椹胚、早期囊胚、囊胚、待扩展囊胚、扩展囊胚、待孵化囊胚和孵化囊胚，经检测其细胞数分别为：４５，６９，７０，８８，１０３，１２７，１３９和１５１。第９ｄ的囊胚细胞数比第７ｄ或第８ｄ的囊胚细胞数无显著差异，然而，不同等级的囊胚的细胞数差异显著（Ｐ＜０．０５）；同时，细胞数少的胚胎发育也慢。通过囊胚免疫法检测，第７ｄ、第８ｄ和第９ｄ回收的扩展囊胚的细胞数分别为６６，６０和５２。此外，虽然在子宫内膜细胞或输卵管细胞－子宫内膜细胞的单层细胞上的囊胚发育慢，且发育率低，但其细胞数与在其它单层细胞上发育的囊胚相比无显著差异。试验结果表明，通过体外化培养出来的囊胚细胞数也能达到体内囊胚的水平。     

苦瓜主要经济性状配合力和遗传相关的研究

6个绿苦瓜自交系分成两组，按不完整双列杂交设计配制9个组合，对苦瓜第一雌花平均节位、雌花数、单果质量、果长、果径和果肉厚等6个经济性状的配合力和遗传相关进行了研究。结果表明：第1组亲本A1、A2和A3仅在果长、果径和果肉厚3个性状上一般配合力效应差异极显著，而第2组亲本B1、B2和B3在6个性状上一般配合力效应差异均极显著。9个组合间仅第一雌花平均节位与果长的特殊配合力效应差异极显著。第一雌花平均节位与雌花数，雌花数与果长，果径与果肉厚，单果质量与果长，第一雌花平均节位与果长。果长与果径，雌花数与单果质量，第一雌花平均节位与单果质量，上述诸项的遗传相关系数r分别为：-1．0．-0．97，0．90，0．82，0．80，-0．78，-0．75和0．73。果长和果径对单果质量的遗传直接通径系数分别为1．37和0．71。     

土壤养分空间变异及合理取样数研究

土壤养分存在明显的空间差异，田间土壤养分合理取样数取决于养分要素自身空间变异程度和人们对数据精度的要求。若空间变异大、精度要求高则需要较多采样数，反之需较少样点数。计算结果表明，极大多数养分要素的合理取样数较实际取样数有较大幅度减少，意味着可大幅降低采样及分析成本。据统计学空间自相关和半方差函数方法研究结果，养分要素存在一定的空间自相关性，但不同方向上的自相关性有明显差异，独立间距也因养分要素而异。研究结果可为精准农业土壤养分样点密度设定、养分要素等值线绘制及精准施肥提供支持。     

高温、高CO2对农作物影响的试验研究

在人工气候室试验研究高温和高CO2浓度对农作物的影响结果表明，高温、高CO2浓度使农作物生育进程加快，作物生育期缩短，作物的光合作用速率升高，蒸腾速率下降和气孔阻力增加；在相同的发育期使作物叶面积、根、茎、叶生长量不足，生物量下降；对不同作物产量结构的影响有差异，对小麦的影响主要是小穗数和穗粒数下降，而对玉米的影响主要是籽粒百粒重下降。高温、高CO2浓度可使农作物叶片中微量元素含量发生显著变化。     

灭幼脲Ⅲ号防治马尾松毛虫效果及其松林昆虫多样性变化研究

湖南省宁乡县是3代类型的马尾松毛虫常灾区，1993年6月第1代应用25％灭幼脲Ⅲ号进行防治。防治后12代通过对灭幼脲＋溴氰菊酯（Ⅲ）和对照（CK）4种类型的松林内昆虫多样性调查表明，各处理区内灌木层物种数和个体数均高于树冠层，未施药对照区物种数高于其他3种处理区，溴氰菊酯施药区物种数最低；但各处理区树冠层和灌木层昆虫多样性指数无显著差异，灌木层昆虫物种多样性有待于进一步丰富；经过12代的持续控制后各处理区昆虫多样性水平已基本得到恢复。     

硫对油菜产量和抗逆性的影响

通过田间小区试验，研究了施用硫肥对油菜的生长、产量构成因素和抗逆性的影响。结果表明，苏北建湖和大丰的潮土尽管土壤有效硫测定值超过临界值，但是，施用硫肥显著促进油菜的生长发育，提高油菜的株高、叶面积、绿叶数等生物学参数和产量。与对照相比，施用硫肥处理的分枝数、每株角果数、每角粒数均显著增加，但千粒重无显著差异。施用硫肥后植株对冻害和菌核病的抵抗力增强。本研究结果表明，对油菜这类需硫量大的作物，现有的土壤有效硫临界值不能准确反映其对硫肥的需要，其缺硫指标要进一步研究。     

台湾青枣盆栽基质的筛选

选用塘泥、菇泥、椰糠3种基质进行6种不同的配比作为台湾青枣的栽培基质，对台湾青枣进行盆栽研究，并以塘泥作为对照。结果表明：不同配方的栽培基质对台湾青枣的营养生长和生殖生长均有不同的影响，其中处理C(塘泥：菇泥=3：2)的新叶片数和花序数与对照A相比差异达到显著水平，开花数达到极显著水平，是台湾青枣盆栽栽培基质的理想配方。     

Influence of Soil Type on Severity of Straighthead in Rice

Straighthead is a physiological disorder of rice (Oryza sativa) that causes symptoms including deformed florets and panicles, floret sterility, and reduced grain yield. Naturally occurring straighthead is very erratic in its expression, hampering efforts to determine its cause and effect. A greenhouse experiment was conducted using soils from four rice fields with variable histories of straighthead occurrence. The experiment included incorporation of zero or 20 t ha^–1 of wheat straw and used two rice varieties of varying tolerances to straighthead, Doongara (susceptible) and Jefferson (tolerant). Relationships between straighthead severity and soil and plant nutrients were investigated. There was a large difference between soils in the rate of soil redox potential decline after flooding, rice growth and yield, and the presence and severity of straighthead. Straighthead score was significantly correlated with decreased grain yield and increased floret sterility. The incorporation of 20 t ha^–1 straw significantly reduced grain yield and increased floret sterility and straighthead scores in three of the four soils. Plant copper (Cu) and magnesium (Mg) were positively and iron (Fe) and molybdenum (Mo) negatively correlated with straighthead score. There were no consistent relationships among soil properties, plant nutrients at panicle initiation, and straighthead severity. The results indicate that no one soil mineral/nutrient is controlling the severity of straighthead but a combination of soil chemical factors may be involved. It is recommended that only straighthead-tolerant rice varieties be grown on soils that have a history of straighthead and the incorporation of stubble prior to rice growing should be avoided in these fields. Further research needs to be conducted into ranking Australian rice varieties on their tolerance to straighthead so farmers can choose the most suitable variety for their field.     

花后增温对双季优质稻产量和品质的影响

为明确未来气候变暖对双季优质稻产量和稻米品质的影响,采用开放式主动增温系统,早稻以金早47(常规籼稻)、两优287(杂交籼稻),晚稻以象牙香珍(常规籼稻)、万象优华占(杂交籼稻)和甬优5550(籼粳杂交稻)为试验材料,研究花后增温对双季优质稻产量和稻米品质的影响。结果表明,花后増温(早稻1.29℃,晚稻1.73℃)对早晚稻产量均无显著影响。增温条件下,早稻加工品质和垩白粒率均无显著变化,垩白度平均提高了16.0%;晚稻糙米率、整精米率、垩白粒率和垩白度分别平均提高了1.8%、3.5%、30.3%和27.2%;早晚稻蛋白质含量平均提高了6.27%,但直链淀粉含量平均降低了3.53%,淀粉颗粒的平均粒径提高了0.09 μm。增温对稻米RVA谱特征值的影响在季别和品种间存在较大变异。综上,花后增温对早晚稻产量无显著影响,有利于改善稻米的加工品质和营养品质,但降低了稻米的外观品质。本研究结果为未来气候变暖下双季优质稻的优质丰产栽培提供了理论依据。     

结合遥感技术与水稻生长模型来预算水稻产量

Since remote sensing can provide information on the actual status of an agricultural crop, the integration betwee nremote sensing data and crop growth simulation models has become an important trend for yield estimation and prediction. The main objective of this research was to combine a rice growth simulation model with remote sensing data to estimate rice grain yield for different growing seasons leading to an assessment of rice yield at regional levels. Integration between NOAA (National Oceanic and Atmospheric Administration) AVHRR (Advanced Very High Resolution Radiometer) data and the rice growth simulation model ORYZA1 to develop a new software, which was named as Rice-SRS Model, resulted in accurate estimates for rice yield in Shaoxing, China, with an estimation error reduced to 1.03% and 0.79% over-estimation and 0.79% under-estimation for early, single and late season rice, respectively. Selecting suitable dates for remote sensing images was an important factor which could influence estimation accuracy. Thus, given the different growing periods for each rice season, four images were needed for early and late rice, while five images were preferable for single season rice. Estimating rice yield using two or three images was possible, however, if images were obtained during the panicle initiation and heading stages.     

机插同步一次性精量施肥对双季稻产量及经济效益的影响

为保证水稻施肥的准确性,揭示水稻机插与同步一次性侧深减量施肥的应用效果,筛选适宜施肥配方,本试验在典型双季稻种植区,以测土配方施肥量为依据,结合精量施肥机,研究机插同步一次性精量施肥对双季稻产量及经济效益的影响,并探讨各构成因素间及其与产量的相互关系。结果表明,侧深施N量和稻季品种对机插双季稻产量、产量构成因素及经济效益具有显著或极显著影响。与常规施肥处理相比,机插同步一次性减N 10%~30%处理的早稻产量和经济效益分别提高16.5%~20.2%和26.4%~31.8%,有效穗数、总颖花数和总实粒数分别提高5.5%~7.5%、8.2%~25.3%和8.3%~27.6%;晚稻产量和经济效益分别提高3.9%~11.1%和12.6%~20.9%,有效穗数、总颖花数和总实粒数分别提高15.8%~22.5%、16.8%~26.5%和14.0%~31.6%。其中,以机插同步一次性减N 20%~30%处理效果较好。水稻机插同步一次性精量施肥随着施N量的降低,双季稻产量、经济效益及有效穗数、总颖花数和总实粒数呈先升高后降低的趋势。回归分析表明,早、晚稻侧深施肥N用量分别为130.0和161.5 kg·hm^-2时达到最大值,即8 538.2和7 459.1 kg·hm^-2。通径分析表明,有效穗数对早、晚稻籽粒产量的直接效应最高。综上所述,通过施肥技术和机插模式的集成与优化,能够有效减少稻田N肥施入,有利于形成有效穗数,扩充籽粒库容,从而达到双季稻生产节肥、省工、增产的目的,为机插同步一次性精量施肥技术应用提供理论支撑。     

稻米爆腰机理与碎米率

碾米过程中产生的碎米率与稻谷中的糙米的爆腰率有重要相关关系。米粒的主要成分是淀粉,淀粉以一定的晶体结构排列在米粒的胚乳细胞壁中,当淀粉在受热和受潮时,淀粉粒膨胀,使米粒产生热应力和水分应力差,当此拉应力大于米粒抗拉强度时,米粒内部就产生裂纹而形成爆腰米粒。稻谷在收获后期、收获后的干燥、贮藏中均会受到温度和水分变动而产生爆腰米粒,稻谷在加工过程中受到机械力的作用也会增加米粒的破碎。所以,降低碎米率应该从稻谷的收获后期就引起注意,防止温度和水分过大的波动,在稻谷加工中米粒应避免拉伸和弯曲的作用。     

Effect of Planting Method on Grain Quality and Nutrient Utilization for No-Tillage Rice

Field experiments were conducted over 2 years using six rice (Oryza Sativa L.) cultivars to investigate the effect of two planting methods, transplanting (TP) and direct sowing (DS), on grain quality and nutrient utilization. Brown and head rice percentages, grain width, amylase, and protein content were greater in TP than in DS, whereas the opposite effect was found for chalkiness rate, gel consistency, and alkali spread value (ASV). Dramatic differences were also found between the two planting methods for nutrient harvest index and utilization efficiency, with TP having greater phosphorus (P) and potassium (K) harvest indexes, nitrogen (N) and K utilization efficiencies, and lower N harvest index and P utilization efficiency than DS. Moreover, significant differences between these genotypes could be found for both nutrient harvest index and utilization efficiency. The correlation analysis showed that rice chalkiness, transparency, gel consistency, amylose, and protein contents were all significantly correlated with N, P, and K nutrient traits. In addition, significant interactions between rice cultivar and planting methods for both rice quality and nutrient traits were also found.     

Zinc Concentration in Rice (Oryza sativa L.) Grains and Allocation in Plants as Affected by Different Zinc Fertilization Strategies

Concern over the food chain transfer of zinc (Zn) is increasing because of its importance in human health. A field experiment was conducted on a low Zn soil to determine the effect of different Zn fertilization strategies on grain Zn concentration and Zn allocation in different plant tissues of rice. Six treatments were used: (1) no Zn fertilization; (2) soil fertilization at transplanting; (3) Zn soil fertilization at transplanting and flowering; (4) foliar application during grain filling; (5) foliar applications during tillering, flowering, and grain filling; and (6) combination of treatments 3 and 5. Zn fertilization significantly increased Zn concentration in brown rice. The largest effect on grain Zn was observed by combination of soil and foliar applications. The increase in brown rice was much smaller (20%) than the increase in the vegetative parts (100%), indicating that grain Zn concentration of rice is not strongly increased by Zn fertilization. More increased Zn by Zn fertilization was allocated into straw not into grain. From the perspective of human nutrition, it seems that there is too little scope to enhance Zn concentration in rice by fertilization alone. the major bottleneck to increase Zn concentration in rice grain seems to be internal translocation/retranslocation of Zn from shoot to panicle or from rachis to grain, rather than root uptake of Zn from the soil.     

耐低磷水稻筛选与鉴定

对2472个来自不同核心种质资源库的代表性水稻品种进行了苗期耐低磷初选和复筛,并通过全生育期鉴定,研究了耐低磷水稻种质资源筛选的基本条件和指标。结果表明,采用两步筛选法,即苗期初筛和复筛,并通过全生育期产量验证,既可以获得典型耐低磷和低磷敏感水稻品种,又提高效率,吻合度达67%;在供试土壤有效磷含量小于5.mg/kg时,筛选密度为4株/600g土,设低磷水平为50.mg/kg(外加);分蘖数及其耐低磷指数(相对分蘖数)综合性较强,作为苗期筛选指标比较适宜;对于少数特殊的品种,它们在高磷和低磷处理时都没有分蘖,此时用干重耐低磷指数(相对干重)来衡量它们的耐低磷能力比较合适;全生育期验证以经济产量及其耐低磷指数(相对经济产量)为鉴定指标,其中有效穗对经济产量影响最大。     

不同抗性稗草对水稻产量及其生理特性的影响

为探讨对除草剂敏感的稗草和产生多抗性的稗草对水稻生长发育的影响,以南粳9108为试验材料,自水稻移栽至成熟分别与对二氯喹啉酸、稻杰和双草醚均敏感的稗草(敏感稗草,T1)和对二氯喹啉酸、稻杰和双草醚均产生抗性的稗草(多抗性稗草,T2)共生,以无稗草水稻处理为对照(CK)。结果表明,与T1相比,T2的分蘖数、干物质积累量和每穗粒数显著降低、生育期缩短,但千粒重显著增加。与稗草共生后,与CK相比,T1和T2的水稻产量分别显著减产32.5%~33.4%和24.8%~26.7%,T2的减产率略低于T1,但二者差异不显著。与CK相比,T1和T2还显著降低了水稻抽穗期水稻叶面积指数、灌浆期叶片光合速率、根系氧化力、根干重、籽粒中玉米素+玉米素核苷、吲哚-3-乙酸含量、蔗糖合成酶和腺苷二磷酸葡萄糖焦磷酸化酶活性和成熟期干物质积累量,T1与T2间差异不显著。水稻叶面积指数、灌浆期叶片光合速率、根系氧化力、根干重、籽粒中玉米素+玉米素核苷、吲哚-3-乙酸含量、蔗糖合成酶和腺苷二磷酸葡萄糖焦磷酸化酶活性和成熟期干物质积累量的显著降低是T1和T2致使水稻产量降低的重要原因。本研究结果为杂草综合治理和水稻高产栽培提供了理论依据。     

基于主成分变换的ASAR数据水稻种植面积提取

合成孔径雷达(SAR)数据是多云多雨地区水稻监测的重要数据源,多极化的SAR数据有利于识别精度的提高。通过对水稻生长期ENVISAT ASAR双极化数据后向散射系数分析得知,水稻VV极化的后向散射系数比VH极化大,两者总体上都随着水稻的生长而增大。在水稻生长后期,VV极化保持稳定,略有下降,VH极化持续增大。对6个通道的ASAR进行主成分变换,发现水稻种植区在第二主分量(PC2)上值较大,色调很亮,而在第五主分量(PC5)上值较低,色调很暗,分别反映了VV极化和VH极化在水稻生长茂盛期与生长初期的差异,两者差值(PC2-PC5)突出了水稻与其它地类的差异。利用主成分分量的差值(PC2-PC5),基于面向对象分类方法,建立了水稻种植区快速提取方法。利用该方法对福州地区2004年早稻面积进行提取,获得了满意的结果。