壳聚糖-山梨酸复合涂膜对宣城圆枣保鲜效果的影响

针对鲜食红枣成熟后贮藏期短,商品性会随贮藏期延长而降低等问题,以宣城圆枣为试材,采用5个浓度(0.1%、0.25%、0.5%、1.0%、1.5%)壳聚糖与浓度为0.1%的山梨酸混合,配制成复合保鲜液,对其进行涂膜保鲜处理。结果表明:在4℃条件下,壳聚糖-山梨酸复合涂膜处理在一定程度上能延缓宣城圆枣果实失重率与腐烂率上升的速度,同时抑制硬度及VC含量的下降,从而延缓果实的成熟衰老进程,提高贮藏品质,延长货架期。通过对各项果实品质指标数据的综合分析得出,复合涂膜溶液的最佳使用浓度为0.25%壳聚糖+0.1%山梨酸。     

农业机械化发展效应的全局密切值法测度

构建了我国农业机械化发展效应测度的ICOE指标体系,应用全局密切值法对我国各省、市、自治区农业机械化发展效应进行测度.根据测度结果将全国各省、市、自治区农业机械化发展效应划分为A、B、C 3个等级,并分析了2004、2006年各省、市、自治区农业机械化发展效应变化的原因.     

Stable resistance against the leaf miner <Emphasis Type="Italic">Leucoptera coffeella</Emphasis> expressed by genetically transformed <Emphasis Type="Italic">Coffea canephora</Emphasis> in a pluriannual field experiment in French Guiana

Summary A pluriannual field trial of transgenic clones of Coffea canephora (the Robusta coffee tree) transformed for resistance to the lepidopteran coffee leaf miner Leucoptera coffeella was installed in French Guiana. Fifty-eight transformed clones produced by transformation of the C. canephora clone 126 were planted. They were harbouring the pEF1α constitutive promoter of Arabidopsis thaliana controlling either the Bacillus thuringiensis native gene for the cry1Ac insecticidal protein (eight clones) or a synthetic cry1Ac gene (53 clones). The vectors for the transformation were a strain of the bacterium Agrobacterium tumefaciens and one of Agrobacterium rhizogenes. The transformed clones were generally independent, presenting different integration patterns of the genetic construct. Four randomly distributed groups of five plants per transformed clone were planted along with 60 untransformed control trees. Over a 4-year period after plantation six releases of L. coffeella were performed. Mines on the leaves are the marks of larvae development and were counted on plants. A majority of the independent transformed clones harbouring the synthetic gene and transformed by the strain of A. tumefaciens displayed constantly much less mines than the control, therefore expressing a stable resistance. The need for complementary research is presented.     

Nitrogen Accumulation and Translocation for Winter Wheat under Different Irrigation Regimes

The translocation of pre‐anthesis nitrogen to the grain is an important source for winter wheat. The relation between the nitrogen translocation and irrigation regime was studied in the field under a rain‐proof trough shelter. Nitrogen (N) translocation amount, N translocation efficiency decreased with a decline in irrigation amount or by excessive irrigation. Compared with different organs, the leaf and stem had higher N translocation amounts, and contributions to grain for both cultivars – Jinan 17 and Lumai 21, indicating that stem also is a major N source for grain development. The contribution of pre‐anthesis total above ground N to grain N ranged from 57 to 76 %, indicating the importance of pre‐anthesis storage of N for achieving high grain N concentrations. Grain nitrogen and yield (kg ha^?1) were positively and significantly correlated with the N translocation amounts and contributions, respectively, suggesting that the sink strength may be involved in the translocation of N from a vegetative organ to the grain. N harvest index (NHI) was significantly correlated with N translocation efficiency, suggesting that the latter is a prerequisite for increasing grain N and improving grain quality. The experiment showed that N translocation status is enhanced by better irrigation practices, but limited by severely deficient or excessive irrigation.     

Grain yield, and dry matter and nitrogen accumulation and remobilization in durum wheat as affected by variety and seeding rate

The influence of crop density on the remobilization of dry matter and nitrogen from vegetative plant parts to the developing grain, was investigated in the durum wheat (Triticum durum Desf.) varieties Creso, Simeto and Svevo cultivated in the field at three seeding rates, 200, 250 and 400 seeds m⁻². Variety × seeding rate interaction was unsignificant for all recorded characters. Grain yield declined in the order Svevo > Simeto > Creso. Yield differences mainly depended on the different number of kernels per unit land and, secondly, on mean kernel weight. Spike components differed among varieties: Svevo and Simeto showed more kernels per spikelet and Creso more spikelets per spike. Grain yield was highest with 400 seeds m⁻² primarily due to the higher number of spikes per unit area, and secondly, to the higher mean kernel weight. Post-heading dry matter accumulation was highest in Svevo and lowest in Creso, but varieties showed a reverse order for dry matter remobilization and contribution of dry matter remobilization to grain yield. The increase of seeding rate increased both the post-heading dry matter accumulation and the dry matter remobilization from vegetative plant parts to grain. Nitrogen uptake of the whole crop and N content of grain was higher in Simeto and Svevo than in Creso. The N concentration of grain did not vary among varieties, but Svevo showed a markedly lower N concentration and N content of culms at maturity, which may be consequence of the high N remobilization efficiency performed by this variety. The N uptake by the crop was highest with 400 seeds m⁻², but the N concentration of culms, leaves and even grain was slightly lower than with the lower seed rates. The post-heading N accumulation was by far higher in Simeto and Svevo than in Creso, whereas remobilization was highest in Svevo and lowest in Simeto. The percentage contribution of N remobilization to grain N was by far higher in Creso than in the other two varieties. Post-heading N accumulation and N remobilization were highest with the highest plant density, but the contribution of N remobilization to N grain content did not differ between seeding rates.     

两系杂交稻两优培九粒重因子的环境模型解析及生态特征分析

为探究两系杂交稻两优培九粒重对气候的反应和生态适应性,用2006年和2007年在南方稻区8个生态点29点次的田间种植试验资料,将粒重解析为谷粒长、宽、厚和比重4个因子,组建了谷粒面积(S)、厚度(H)和比重(ρ)的环境预测模型。相关分析表明,谷粒面积S的影响期在颖花分化期(III~IV期)至花粉母细胞减数分裂期(VI~VII期),温度是其主要影响因子,有利于谷粒长度和宽度发育的日平均气温( )为27~29℃,最高气温(T_max) 34℃,最低气温(T_min) 24℃。谷粒厚度H与抽穗后1~30 d的Tmax呈二次曲线关系,与 呈负相关。谷粒比重ρ与日照时数(SH)呈正相关,影响时期在抽穗后1~10 d;与Tmax呈负相关,影响时期在抽穗后1~30 d。有利于增加ρ的气象指标是SH达到8 h,T_max低于30℃。用1951—2002年的气候资料模拟计算了95个地区的两优培九千粒重,按7个水稻生态区归纳,平均值变化在25.93~28.01 g之间。千粒重的区域分布明显随纬度而递增,由于地形影响,在湘、赣、粤北地区还表现出一定的经向影响。晚季稻的千粒重则比早季稻高1.39 g。幼穗分化期的温度和灌浆结实期的温度、日照时数是造成两优培九粒重区域和季节特征的主要生态原因。     

豇豆胰蛋白酶抑制剂转基因棉花的获得

利用根癌农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍｔｕｍｅｆａｃｉｅｎｓ）介导法将豇豆胰蛋白酶抑制剂（Ｃｏｗ－ｐｅａＴｒｙｐｓｉｎＩｎｈｉｂｉｔｏｒ,ＣｐＴＩ）基因转移进入棉花（ＧｏｓｙｐｉｕｍｈｉｒｓｕｔｕｍＬ．）。棉花幼苗的下胚轴与携带有ＣｐＴＩ基因和Ｎｐｔ－Ⅱ基因的根癌农杆菌共培养,在选择培养基上诱导出了卡那霉素抗性（Ｋｍｒ）愈伤组织。选择Ｎｐｔ－Ⅱ阳性的胚性愈伤组织在胚状体诱导培养基上进行胚状体诱导,继而在分化培养基上进行植株分化,最终获得了再生棉花植株。经Ｎｐｔ－Ⅱ分析、ＰＣＲ及Ｓｏｕｔｈｅｒｎ检测证明,外源ＣｐＴＩ基因和标记基因（Ｎｐｔ－Ⅱ基因）存在于转化棉株及其后代中。抗棉铃虫（Ｈｅｌｉｏｔｈｉｓａｒｍｉｇｅｒａ）生物活性检测表明转基因植株后代具有明显的抗棉铃虫能力。     

The Optimization for Crop Planning and Some Advances for Water-Saving Crop Planning in the Semiarid Loess Plateau of China

The establishment of water-saving crop planning is an inevitable choice of the water-saving agriculture for the water-deficiency region in the arid and semiarid Loess Plateau of China and the world. The water-saving crop planning refers to the planting structure that centres the adjustment of the crop's adaptation to water, the optimization of temporal and spatial layout for crops, the local natural resources, marketing resources, human resources and financial input to enable region or basin with limited water resources to achieve the maximum economic, social and ecological benefits of planting industry under certain technology and economy. After the analysis on the research progress of optimization theory, optimization goals, optimization methods of water-saving cultivation structure and macro-control measures, it is pointed out that the main deficiencies of the current research of water-saving cultivation pattern optimization are lacking of a strong theoretical basis, and the immaturity of optimization technologies. The future crucial research direction will focus on five aspects such as the special optimization theory system, the division methods by studying the watershed unit and using 3S technology, optimization model based on multi-objective evolutionary algorithm, evaluation of rationality and macro-control measures on the basis of the public participation.     

Production of mutants with high cold tolerance in spring canola (<Emphasis Type="Italic">Brassica napus</Emphasis>)

A major factor affecting spring canola (Brassica napus) production in Canada is killing frosts during seedling development in the spring and seed maturation in the fall. The objective of this study was to explore the possibility of producing spring canola lines with mutations that have altered biochemical pathways that increase cold tolerance. The approach was to generate UV point mutations in cultured microspores followed by chemical in vitro selection of individual mutant microspores or embryos resulting in measurable alterations to various biochemical pathways with elevated levels of key defense signaling molecules such as, salicylic acid (SA), p-Fluoro-d,l-Phenyl Alanine (FPA), and jasmonic acid (JA). In addition, since proline (Pro) is known to protect plant tissues in the cold-induced osmotic stress pathway, mutants that overproduce Pro were selected in vitro by using three Pro analogues: hydroxyproline (HP), azetidine-2-carboxylate (A2C); and, 3,4-dehydro-d,l-proline (DP). Of the 329 in vitro selected mutant embryos produced, 74 were identified with significant cold tolerance compared to their donor parents through indoor freezer tests at −6°C, and 19 had better winter field survival than winter canola checks. All chemically selected mutant doubled haploids with increased cold tolerance compared well with parent lines for all seed quality and agronomic parameters. Development of increased frost tolerant cultivars should allow for spring canola to be produced in western Canada without compromising seed quality.     

The genetic relationship between popping expansion volume and two yield components in popcorn using unconditional and conditional QTL analysis

Popping expansion volume (PEV) is the most important quality trait in popcorn, while its germplasm is inferior to normal dent/flint corn in yield. In this study, 259 F_2:3 families, developed from the cross between a dent corn inbred Dan232 and a popcorn inbred N04, were evaluated for their PEV, grain weight per plant (GWP) and 100-grain weight (100 GW) in two environments. The genetic relationship between PEV and GWP, and 100 GW on individual gene loci were evaluated using unconditional and conditional QTL mapping methods. In total, five, one and three unconditional QTL were identified for PEV, GWP, and 100 GW, respectively. The positive alleles of all QTL for PEV were from N04, while positive alleles of all QTL for GWP and 100 GW were from Dan232. In conditional mapping, one and two QTL failed to be detected, and all four additional QTL were detected. Nevertheless, three QTL were identified, which controlled PEV independently from GWP/100 GW. They seemed to be potential candidates in popcorn breeding to increase PEV without decreasing GWP/100 GW. The results suggested that for significantly correlated traits, the conditional QTL mapping method could be used to dissect the genetic interrelationship between traits at the level of individual QTL, as well as reveal additional QTL that were undetectable by unconditional mapping.