山桐子实生优树选择研究初报

以四川等8个省份的山桐子野生资源为研究对象,通过实地走访和调查,了解山桐子资源分布状况和生态环境,利用产量、含油率等经济性状对山桐子野生群体进行优株选择。结果表明:安徽、江苏、浙江、江西各地主要以山桐子分布,而湖北、湖南、陕西、四川等地主要以山桐子的变异类型——毛叶山桐子为主,其中四川省毛叶山桐子分布较为密集;通过对各地点气候条件和土壤条件分析得出,山桐子适应性强,对气候要求不严,适合在微酸性土壤生长,尤喜肥沃土壤;根据能源油料植物原则对山桐子提出选优标准,从234株山桐子实生树中初步选择43个单株;主成分分析和聚类分析结果将43个单株划分为最高产量、较高产量和中产量3大类,且所有单株的单株产量、单位面积产量和全果含油率3个主要经济指标均高出群体平均值20%以上。本研究为山桐子种质资源收集与评价、优良种质或品种的选育奠定了重要基础。     

Size distribution,growth and inter-year variation in sex expression of Bischofia javanica,an invasive tree

Flowering activity and sex expression of Bischofia javanica Blume were investigated for 3 years. B. javanica is an invasive dioecious tree of subtropical forests on the Bonin Islands in the western Pacific of Japan. The sex ratio showed a significant male bias (1.25-2.33). Smaller trees were significantly male biased, whereas larger trees showed no significant difference in sex expression, suggesting that males tend to be more precocious in sexual reproduction. We found evidence for sex changes in B. javanica; these have not been reported previously. Most of the 1,653 census trees remained non-flowering (58.1 %); 3.7 % of them showed sex changes, and the percentage of trees repeatedly flowering as males and females was 10.5 and 3.4 %, respectively. Sex changes were observed in both directions but a larger percentage of male trees became female. Flowering frequency and sex expression were significantly related to tree size (i.e. diameter at breast height). Over the 3 years, trees that were consistent females were the largest; inconsistent trees (switching sex between years) were intermediate in size, whereas consistent males were the smallest. There were no significant differences in relative growth rate (RGR) among trees of different sex or flowering frequencies. These results suggest that the maintenance of female reproduction is not related to changes in RGR of diameter but to flowering frequency or the reversal to the male form, dependent upon the internal resource status of individual trees.     

Effects of microenvironment on net photosynthetic rate and growth of four tropical species in the La Mesa watershed

Seedlings of four tree species (Bischofia javanica, Dracontomelon dao, Erythrina orientalis, and Pterocarpus indicus) were planted in flat and sloping grassland in plantation sites established in May 2002 in the La Mesa watershed, Philippines. Tree growth and net photosynthetic rate (P _N) were monitored. The height, diameter at the root collar, and P _N of the four species grown in the sloping grass site were larger than those of seedlings grown in the flat grass site. In addition, soil moisture contents in the sloping grass site were higher than those of the flat grass site. Growth of the four species was probably strongly associated with microenvironments (e.g. air temperature) in both tested sites.     

Two Unearthed Ancient Woods Excavated from Wuhan City

Two unearthed ancient woods were excavated from 45–47 m underground Wuhan city (Hubei Province) in 1990. One of the woods was identified to be a coniferous wood: and named as Metasequoia glyptostroboides Hu et Cheng, and the other as broadleaf wood: Bischofia polycarpa Airy-Shaw. The geologic age is considered to be in the late Pleistocene of Quaternary about 11280 ±190 years from present.     

山桐子雌、雄株叶片表皮微形态特征的比较研究

【目的】探究山桐子（Idesia polycarpa Maxim.）叶片表皮微形态特征及其雌、雄株差异,为该种质资源的挖掘利用提供参考。【方法】利用扫描电镜,对40份山桐子（雌、雄株各半）叶片进行微形态观察,测定12个气孔相关性状,并分析样品间的异同。【结果】（1）山桐子雌、雄株叶片的表皮毛、细胞形态、气孔特征及蜡质式样相似,其下表皮密布的类锥形纤维体型蜡质纹饰,鲜见于其它植物类群。（2）山桐子雌株叶片的气孔大小（长度、宽度、面积及周长）及密度相关参数均略大于雄株;雄株叶片的气孔开口相关参数（孔隙宽度、开口面积及气孔开度）均略高于雌株;但所有差异均未达到统计学显著水平（P > 0.05）。（3）多数气孔性状彼此显著相关,而气孔密度与其它性状关联较弱,可能受到相对独立的遗传调控。【结论】本研究首次明确了山桐子叶片表皮的微形态特征,其类锥形纤维体型蜡质式样可作为种质评鉴的关键依据,其气孔性状参数可为童期种苗的性别判定提供重要参考。     

广西大戟科一些属的分类简志

<正> 大戟科在广西植物区系中为大科之一,约50属,200种以上,广布区内各地,但热带性较强的种类主要见于桂东南经桂南至桂西北山区。近年来笔者在编写《广西植物志》第二卷工作中,按分工要求,对所承担的属的馆藏标本作了全面整理研究。现将研究结果报道,以资利用。本文共记载19属56种。     

The influence of emergent trees on rainfall distribution in a cacao agroforest (Sulawesi,Indonesia)

Emergent trees may have an influence on the volume and the spatial distribution of water input into agroforestry stands and may thus affect water availability for the main crops. Our goal was to analyze the influence of such trees on rainfall distribution in a cacao agroforest area in the rainforest margin zone of Central Sulawesi, Indonesia. The emergent trees studied belong to the species Bischofia javanica (Phyllanthaceae) and were 15 m high remnants from the natural forest. A set of 96 throughfall gauges was systematically distributed underneath canopies of cacao only, and underneath canopies of cacao plus emergent trees (cacao plus trees). From an earlier study we knew that stemflow can safely be estimated with less than 1% of gross precipitation (Pg).     

遮荫处理对秋枫幼苗生理生态特性的影响

为了解遮荫对秋枫(Bischofia javanica)幼苗生长的影响,对夏季1年生秋枫幼苗在4种遮荫(透光率分别为自然光的100%、41.3%、14.6%和3.6%)处理150 d后的生理指标变化进行了研究。结果表明,1年生秋枫幼苗的光补偿点(LCP)、光饱和点(LSP)和暗呼吸速率(Rd)随着遮荫程度加重而减小,表观量子效率(AQY)则增大,净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和胞间CO_2浓度(Ci)的日变化表明秋枫有明显的"午休"现象,遮荫引起光合速率降低的主要原因是非气孔限制,而全光照条件下则是气孔限制。叶绿素、可溶性糖含量随遮荫程度的增大呈先升后降的变化趋势;相对电导率、丙二醛(MDA)含量、过氧化氢酶(CAT)活性则呈先降后升的趋势,以41.3%透光率的最小;可溶性蛋白质含量、超氧化物歧化酶(SOD)活性随遮荫程度的增大而降低。因此,秋枫幼苗主要通过提高Pn、抗氧化酶活性(SOD和CAT)、叶绿素含量,降低LSP、LCP和Rd,增大AQY来提高弱光利用能力;适度遮荫(41.3%NS)更有利于1年生秋枫幼苗在夏季的生长。     

水冬瓜果肉的非油脂化学成分

经柱层析方法从水冬瓜（Idesia polycarpa var.uestita Diels）果实乙醇提取物的非油脂部分分离纯化出6个化合物,其结构通过波谱分析分别鉴定为去甲松柏苷（I）,idesin（Ⅱ）,salirepin（Ⅲ）,idescarpin（Ⅳ）,1,2-顺-环己二醇（Ⅴ）和邻苯二酚（Ⅵ）。其中化合物I为首次从天然界分离得到。