Evolution of reproductive behaviour in the genus eleusine

Summary The paper traces shifts in the reproductive behaviour as influenced by the selective pressures of crop domestication, in the genus Eleusine, from the wild species. E. africana to its domesticated form E. coracana. Among other changes we consider temporal features of flowering, nature of anthesis and dehiscence, the stigma to lemma length ratio determining the extent of stigma protrusion and the pollen grain to ovule ratio as important in changing the breeding behaviours. These changes are viewed as evolutionary responses of plants to their respective ecological niches.     

萱草花粉微管蛋白的生物化学性质

以萱草花粉为材料，采用丙酮粉法、QAE-Sephadexaso离子交换层析及FPLC技术作为主要分离纯化手段，纯化了毫克数量的萱草花粉微管蛋白，并研究了微管蛋白的生物化学及生物物理学部分性质。试验结果表明：纯化的微管蛋白在20℃时沉降系数为6．2s；α、β2个亚基的分子量分别为56，58kD；凝胶扫描分析纯度为93．7％；等电聚焦电泳测定等电点（PI）为5．35。光谱学性质研究表明其最大紫外吸收峰为280．8nm；荧光光谱研究表明其最大激发波长为282nm，此时的最大发射峰为338nm；圆二色光谱分析二级结构是α-螺旋占27．24％、β-折叠占24．48％、无规则卷曲为48．28％，呈典型球蛋白特征。     

空气花粉污染研究的现状与趋势

阐述了花粉污染与花粉症的概念,国内外空气花粉污染的研究现状,花粉污染的特点以及致敏植物的种类,提出了城市绿化中花粉污染的防治措施,并指出了研究中存在的问题,对研究前景进行了展望。       

Reduction of pollen contamination in Scots pine seed orchard crop by tent isolation

This study examined the differences in mating system between indoor versus outdoor Scots pine (Pinus sylvestris L.) seed orchard using DNA markers. By analyzing the paternities in seed crops from isolation tents, we found a significant reduction in contamination rate, from 23% in the outdoor open blocks to 0% inside the tents. Increase in selfing rate and a decrease in genetic diversity in the crops were also observed inside the tents. These undesirable effects can be mitigated to some extent by the supplementation of extra pollen genotypes, e.g. selfing rate decreased from 14.4% to 6.6% and the effective number of fathers increased from 6 to 11.4 in the tents without and with supplemental mass pollination, respectively. Our study showed that tent isolation may become an effective rescuer for seed orchards where pollen contamination is severe.     

我国西部白刺属及其近缘属的花粉形态与分类

本文借助光学显微镜和扫描电镜 ,对蒺藜科 5属 11种植物的花粉形态进行了观察和研究 ,探讨了花粉形态特征的分类学意义。结果表明白刺属与蒺藜科其他属花粉粒大小和外壁纹饰可作为分属、分科 ,而且分种的依据。同时结果也支持白刺属提升为白刺科 (Nitrariaceae)。本文依据花粉形态和其他器官特征 ,对本属花粉外壁的演化趋势及属的分类地位进行了探讨。这对白刺属的系统、起源与演化的研究提供依据和参考。     

Different breeding systems of three varieties of Bidens pilosa in Taiwan

Three varieties of the introduced Bidens pilosa (Hairy beggar‐ticks; Asteraceae) co‐exist in Taiwan. Bidens pilosa var. minor and var. pilosa are naturalised, while only var. radiata is invasive. Differences in seed set in bagged versus open‐pollinated capitula, pollen–pistil interactions and the pollen/ovule (P/O) ratio were investigated among these three varieties. In contrast with the resulting 45–55% seed set in each bagged capitulum of var. minor and var. pilosa, almost no mature seeds (1–2 seeds) were found in bagged capitula of var. radiata, showing that var. radiata has a low capability of autonomous seed production. In bagged capitula, only 1.5% of pistils of var. radiata, but 76% and 52% of those of var. minor and pilosa, respectively, had pollen tubes penetrating into their styles, suggesting that var. radiata has strong self‐incompatibility mechanisms preventing autonomous autogamy. The P/O ratio, with mean values of 8189, 2053 and 1613 for var. radiata, var. minor and var. pilosa, respectively, were counted. These results support the hypothesis that the three varieties bear different breeding systems; the invasive var. radiata is highly self‐incompatible, whereas the other two naturalised varieties are self‐compatible.     

Insecticide-resistant pollen beetles (Meligethes aeneus F) found in Danish oilseed rape (Brassica napus L) fields

The pollen beetle is the most important pest in Danish oilseed rape fields. In 2001, we screened a broad range of pollen beetle populations for pyrethroid and dimethoate resistance. A standard dip-test was used to test insecticide resistance in 18 populations collected from oilseed winter and spring rape fields. The beetles were treated with four different insecticides: the pyrethroids tau-fluvalinate, lambda-cyhalothrin and esfenvalerate, and the organophosphate dimethoate. The results show that up to 99% of the pollen beetles survived Danish standard doses of pyrethroids and up to 36% of the beetles survived standard doses of dimethoate.     

海原剖面12.5-7.2kaBP期间化学元素与粒度组成的古环境意义

宁夏南部海原剖面12.5-7.2 kaBP期间的地球化学元素含量与粒度组成的环境指示意义显著,主要表现为冷干气候条件下植被稀疏,上游及坡面植被水土保持能力低造成粗颗粒物质含量较多,易溶元素如Na氧化物较多被淋失,难溶解的Si、Al、Fe氧化物相对富集;暖湿气候条件下植被发育良好,剖面沉积的细颗粒物质含量较多,土壤中Na...     

丝瓜花粉对少毛钝绥螨发育和繁殖的影响

丝瓜花粉是饲养捕食螨的常用替代食物,本研究旨在评价应用丝瓜花粉饲养少毛钝绥螨的可行性。在室内条件下,研究了25、30、35℃下少毛钝绥螨以丝瓜花粉为食物后的生长发育和繁殖能力。在25~35℃下,卵至成螨发育历期为3.63~6.96d,发育历期随温度升高逐渐缩短,存活率为82.69%~88.46%。30℃时,总产卵量最高,为41.27粒,净生殖率最高为18.15。产卵持续期随温度升高而降低。内禀增长率在30℃、35℃下显著高于25℃时,最高值为30℃下的0.203。本研究表明,丝瓜花粉是饲养少毛钝绥螨较好的替代食物。     

应用dot-ELISA和RT-PCR法检测玉米花粉中玉米矮花叶病毒的研究

 首次采用dot-ELISA和RT-PCR 2种方法对受玉米矮花叶病毒(MDMV)侵染的玉米品种330、478、黄早四、获白及M o17病株上采得的花粉进行了检测,结果表明2种方法在供试玉米病株花粉中均检测不到MDMV,证明玉米花粉中带或存在玉米矮花叶病毒的可能性很小