油梨果实的生长和内含物变化的观察

本文报道对油梨果实的生长及内含物的变化的观察结果．果实生长发育过程中,以６—７份生长最快,干物质及脂肪含量由低到高变化,以１１月份增加最快,蛋白质含量由高到低递诚．１１月份后含量相对稳定,总糖和维生素Ｃ含量随果实的发育程度而下降。     

Effect of morphine and abstinence syndrome on [3H]bromoxidine binding to α2-adrenoreceptors in rat brain

At 4 days after the implantation of two subcutaneous 75 mg morphine pellets in the back skin, rats were morphine-dependent. In the three layers studied in the occipital cortex we found that the values of the ₂-adrenergic agonist [³H]bromoxidine binding increased with respect to animals implanted with placebo pellets. Typical behavioral and physiological symptoms of the abstinence syndrome appeared 30 minutes after administration of naloxone, [³H]bromoxidine binding values being similar to those obtained in animals implanted with placebo pellets. The pattern of response of the [³H]bromoxidine binding was similar in the hippocampus and the superficial gray layer of the superior colliculus of the mesencephalon, but the differences were not statistically significant in these areas. This paper concludes that exist brain regional differences in the ₂-adrenoreceptors response under morphine-treatment and possibly under naloxone-induced morphine abstinence syndrome.     

Self-fertility and associated flower head traits in the Iberian taxa ofLactuca and related genera (Asteraceae: Lactuceae)

Sexual reproduction is the main reproduction mechanism among the 14 wild Iberian taxa ofLactuca, Prenanthes, Cicerbita, andMycelis. High levels of self-fertilization occur inLactuca, as well as facultative and obligate xenogamy. Xenogamy is strongly correlated with large capitula having blue or bright yellow colouration, high P/O ratios, and long anthesis, whereas self-fertilization is correlated with smaller capitula having pale yellow colouration, small P/O ratios, and short anthesis. Large variations occur in P/O index among taxa showing similar fertilization mechanism, probably in relation to the number of florets included in flower heads. Interesting differences in reproductive systems have been detected between subspecies ofLactuca viminea.     

小麦叶蜂危害的产量损失与防治指标研究

当小麦叶蜂幼虫数量相等时,在较干旱的年份（1988）危害较重;而在气候较湿润的年份（1989）危害较轻。虫量与产量损失成正相关（r=0．9821**）,其中以25头／m2幼虫危害的产量损失突增,达显著水平,可以认定为防治指标。     

祁连山地区植被特征及其分布规律

分析和讨论了祁连山地区主要植被类型及其分布特征。祁连山地区随着青藏高原的强烈隆升表现为整体抬升,植被具有明显的生态地理边缘效应特征和高原地带性规律。该区植被虽然受到四周的较大影响,但各类高寒植被占有绝对优势,表现出与青藏高原植被整体明显的相似性和广泛的一致性。另一方面,本区植被也有其特殊性及与高原面存在一些差异。因此,建议把祁连山地区做为青藏高原植被区的次一级独立单元     

水分胁迫对小麦光系统Ⅱ的影响

水分胁迫可降低小麦叶绿体的室温荧光产量和Ｍｇ２＋ 在两个光系统间的调节能力、叶片的可变荧光产量、可变荧光猝灭速率以及荧光上升互补面积,表明光系统Ⅱ受到了伤害。光系统Ⅱ氧化侧的人工电子供体ＤＰＣ能部分恢复受到抑制的叶绿体可变荧光,说明水分胁迫对光系统Ⅱ的损伤部位不仅位于氧化侧,也可能在反应中心上     

离体条件下诱导番茄果实状结构的再生

以番茄（Ｌｙｃｏｐｅｒｓｉｃｏｎ ｅｓｃｕｌｅｎｔｕｍ Ｍｉｌｌ．）雌蕊和幼果的组织作外植体可以诱导果实状结构的再生。这种果实状结构在离体条件下能培养成熟,成熟时具红色。解剖观察表明：果实状结构由果肉和包围在外面的果皮组成,无种子和胎座。外源激素和外植体年龄的试验揭示：１．以雌蕊组织作外植体时,仅附加外源细胞分裂素就可以诱导果实状结构的再生,外源生长素似乎不是必需的,最高的诱导频率（５０．０％ ）出现在仅附加玉米素０．５ ｍ ｇ／Ｌ的组合。２．从直径４—１２ ｍ ｍ 的幼果上分离的外植体在附加外源激素的培养基上均可诱导果实状结构的再生,但只有从直径８ ｍ ｍ 的果实分离的组织块作外植体并将它们培养在６－ＢＡＰ ２ ｍ ｇ／Ｌ,ＮＡＡ０．１ ｍ ｇ／Ｌ的培养基上时,果实状结构的诱导频率最高（６２．５％ ）。为了探讨在果实状结构再生中表现出来的细胞全能性的表达,提出了植物细胞全能性的部分表达（Ｐａｒｔｉａｌｅｘｐｒｅｓｓｉｏｎ ｏｆｐｌａｎｔ ｃｅｌｌｔｏｔｉｐｏｔｅｎｃｙ）的概念并进行了讨论。     

质体醌重组的D1／D2／Cytb559复合物的荧光衰减动力学和光破坏作用

光系统Ⅱ反应中心Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 在分离纯化过程中失去了电子受体ＱＡ 和ＱＢ,人工合成的质体醌可以与Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 复合物发生重组。癸基质体醌（ＤＰＱ）与Ｄ１／Ｄ２／Ｃｙｔｂ５９９ 复合物的重组导致该复合物的荧光强度下降及发射光谱蓝移,同时两个与光化学活性相关的长寿命（２４ ｎｓ和７３ ｎｓ）荧光衰减组分占整个荧光的百分数下降,这些结果表明ＤＰＱ作为Ｐｈｅｏ－ 的电子受体,限制了Ｐ６８０＋ ·Ｐｈｅｏ－ 的电荷重组。ＤＰＱ 的加入对Ｄ１／Ｄ２／Ｃｙｔｂ５５９复合物中Ｃｈｌａ 分子的光破坏敏感性影响不大,但β－胡萝卜素在加入ＤＰＱ 之后可以被光照破坏,这个过程可能与β－胡萝卜素的生理功能相关。     

A descriptive study of some Antarctic notaspidean opisthobranchs (Gastropoda), with description of a new genus and species

During the expedition “ANTARTIDA 9101”, organized by the Spanish Oceanographic Institute to the South Orkney Islands, four specimens of notaspidean gastropods were collected. Three of them have been identified as Bathyberthella antarctica Willan and Bertsch, 1987. However, one specimen, although externally similar to B. antarctica, had an internal anatomy exhibiting features that have enabled us to consider it to be a new genus and species. This new taxon is characterized by the presence of jaws without mandibular elements, and a vaginal gland that partially surrounds the distal region of the vaginal duct. In this paper the new genus and species is described. Additional anatomical data of the specimens of B. antarctica collected during the expedition are also included.     

Mother-cub relationships in giant pandas in the Qinling Mountains,China, with comment on rescuing abandoned cubs

Six cases of mother-cub relationships in wild giant pandas (Ailuropoda melanoleuca) were observed in the Qinling Mountains, China. It was found that panda cubs are normally left alone in the den for 4–8 h while mothers forage. The mother's absence during bouts of foraging should be considered when rescuing abandoned cubs in order to avoid adding to the decline of the wild population. © 1994 Wiley-Liss, Inc.