不同水分和双网无梗囊霉对黄芩生长和养分含量的影响

利用土培试验,研究不同水分条件下接种双网无梗囊霉(Acaulospora bireticulata)对黄芩(Scutellaria baicalensis)生长和养分含量的影响。结果表明,接种双网无梗囊霉能缓解水分胁迫对黄芩生长的抑制效应,显著提高黄芩干质量、株高、根冠比和菌根侵染率。接种双网无梗囊霉对植株黄芩苷含量和P、N、Mg、K、Ca、Fe、Zn、茎叶Cu含量有促进作用,明显降低了植株Mn和根部Cu含量。说明接种双网无梗囊霉,能够促进黄芩生长和矿质元素吸收,提高植株养分含量和抗旱性。     

蓝光和红光对菊花生长和开花的影响

蓝光光质下培育的菊花比自然光下培育的菊花叶绿素含量、净光合速率、叶片氨基酸总量、糖类含量分别提高２４．６％、３９．７％、３２．０％、８．９％。蓝光光质有利于菊花茎叶生长和侧枝产生,形成丰满株形,并能提前花期１２ｄ。     

印度产紫菜Pyropia chauhanii的细胞学观察

本文对印度产紫菜Pyropia chauhanii不同生活史阶段的染色体进行了系统细胞学观察。用卡诺氏固定液分别对室内培养的P. chauhanii各生活史阶段的活体组织进行固定后,置有光照处使组织色素体褪至约无色,用醋酸铁苏木精染色液对组织作染色和压片处理后进行显微观察。观察结果表明：叶状体阶段的营养细胞、精子囊内未成熟精子和果胞均为单倍核型（n=3）;丝状体阶段的果孢子、丝状体的营养细胞和膨大细胞均为双倍核型（2n=6）;由丝状体产生的壳孢子在萌发初期发生减数分裂后,由双倍核型（2n=6）变成了单倍核型（n=3）。当叶状体发生单性生殖产生丝状体时,游离出来的类果孢子发生染色体自然加倍,其萌发体和随后形成的丝状体营养细胞和膨大藻丝细胞均为双倍核相（2n=6）。当叶状体产生单孢子进行无性繁殖时,单孢子和其萌发体的细胞均为单倍核型（n=3）。     

Interaction of genotype × management on vegetative growth and weed suppression of aerobic rice

Water shortage in drought-prone rice-growing areas of the world is threatening conventional irrigated rice production systems, in which rice is transplanted into fields where standing water is maintained until harvest. Aerobic rice production systems, in which rice is grown as a direct-seeded upland crop without flooding, require less water than conventional systems, but the transition to aerobic rice systems is impeded by severe weed infestation. An environmentally friendly and less labor-intensive weed control method needs to be introduced to aerobic rice farmers. A study was conducted at the International Rice Research Institute in the 2003 wet season and 2004 dry season to evaluate the effects of genotype, seeding rate, seed priming and their interactions on vegetative growth, yield and weed suppression. Three contrasting aerobic rice genotypes differing in yield and weed-suppressive ability (WSA) were grown at three seeding rates (100, 300 and 500 viable seeds m⁻²) with or without seed priming under two weed management treatments (weed-free and weedy) in a split-plot design. In 2004, the overall weed pressure was higher than in 2003, and consequently treatment effects in this year were more distinct than in 2003. No significant interactions among the experimental factors were found for crop yield, weed biomass, leaf area index, tiller number and vegetative crop biomass. Raising seeding rate from 100 to 300 viable seeds m⁻² resulted in a significant increase in yield and a decrease in weed biomass, whereas a further increase from 300 to 500 viable seeds m⁻² did not result in a further improvement in yield and weed suppression. The stronger WSA of genotype Apo than that of genotypes IR60080-46A and IRAT 216 related to a stronger competitive ability of individual plants and a faster canopy closure (0.5–6 days earlier). The WSA of weakly competitive genotypes was partially compensated for by a higher seeding rate. Seed priming, which was only evaluated in 2003, accelerated emergence by 2 days and slightly enhanced early crop growth, but had no significant effect on yield and weed suppression. The present study suggests that combining a weed-suppressive genotype with an optimum seeding rate can serve as a tool to manage weeds.     

海南省香蕉枯萎菌nit突变体的筛选及鉴定

将23个有致病力的香蕉枯萎病菌海南菌株及属于1,4号生理小种菌株Foc-18,Foc-38分别在含氯酸盐的KPS培养基上培养,23个菌株共产生142个抗氯酸盐突变体,诱发获得98个不能利用硝酸盐的营养缺陷突变体。将获得的nit突变株作营养体亲和性配对试验,可将23个菌株分为4个亲和群,其中VCG1包括11个菌株,且全为海南分离的1号生理小种,VCG2则由10个海南4号小种菌株组成,广东1号小种Foc-18,4号小种Foc-38分别属于VCG3,VCG4。     

大豆生育期相关的QTL分析

采用来自Charleston×东农594的143个重组自交系(RILs),构建了1个含有20条连锁群的大豆遗传连锁图谱,对大豆营养生长期、生殖牛长期、发育期进行QTL分析,以期探索大豆生育期相关基因的遗传机理.结果表明:采用复合区间作图法共定位了 6个显著影响营养生长期的QTL位点,分布在A1、H、K、N连锁群上;定位了6个显著影响大豆生殖生长期的QTL位点,其中4个,reA1-2、reH、reK、reN也同时控制营养生长期的长短;在整个生育期定位到8个QTL位点,有5个位点能解释20%以上的表型变异.     

甘蓝型油菜腋芽扦插繁殖研究

采用５个甘蓝型油菜材料进行田间扦插试验,结果表明：甘蓝型油菜腋芽或薹茎在土壤中易生根成苗。１００＊１０＾－６ＡＢＴ、５０＊１０＾－６ＡＢＴ２、１００＊１０＾－６ＮＡＡ对诱导腋芽在土壤中生根的效果良好,生根率达到８３．３％－１００．０％。扦插腋芽宜带三叶,苗床土壤须水分充足,９月中旬至１１月上旬是适宜扦插繁殖的时期,繁殖系数为５－７。     

山蚂蝗属（Desmodium Desv.）营养期营养成分分析

对17份山蚂蝗材料营养期的营养成分进行测定与分析。结果表明:(1)粗蛋白含量最高的为CIAT3787(D.hererocarpum)(22.34%),其次是CIAT46562(D.dunniinicaraguense)(22.32%);粗纤维含量最高的是CIAT13218(D.velutinum)(38.70%),显著高于其他品系(p>0.05);(2)山蚂蝗营养成分之间存在不同程度的相关性,粗纤维含量分别与粗灰分、无氮浸出物、磷的含量存在极显著负相关,粗灰分含量与磷含量有极显著正相关,与钙含量有显著相关;(3)通过聚类分析,在欧氏距离8.0处,可将17份供试山蚂蝗材料划分为3类,其中CIAT46562和CPI46561(D.incanum)单独聚为一类。     

武夷大红袍无性繁殖子代与母代的香味成分比较

分析比较了武夷山大红袍的无性繁殖后代与其母株间的生化成分及品质的差异。结果表明在岩区内生产的无性繁殖大红袍岩茶基本保持了母株的优良品质特性和特征     

黄土丘陵沟壑区封禁流域立地因子对植物群落特征的影响

[目的]研究黄土丘陵沟壑区封禁流域立地因子对植物群落特征的影响。[方法]通过对陕西吴起县内封禁流域进行植被调查,研究了不同立地类型内植被群落特征和物种多样性的差异。[结果]调查区域内植被群落以旱生草本植物为主,物种组成相对单一,结构简单。地带性植被类型为铁杆蒿（Artemisia sacrorum）＋茭蒿（Artemisia giraldii）群落;植物多样性在不同地貌部位表现为梁顶〉沟底〉梁坡〉沟坡,在不同坡向表现为半阴坡〉阴坡〉半阳坡〉阳坡;阳坡多样性指数随坡度的增加表现为＂S＂形变化趋势,37°左右达到最大值。[结论]为黄土丘陵沟壑区的植物恢复提供了理论依据。