中国银杏的种核类型及其特征

银杏种内变异较大。 2 0世纪 5 0年代起 ,通过广泛调查、收集我国银杏的核用品种资源 ,对种实不同发育时期的组织结构及形态特征进行了解剖观察。主要根据种实的珠托、种核的形状、长、宽、厚及种核两侧、顶端的特征 ,将银杏种核分为长子、佛指、马铃、梅核、圆子 5种类型 ,并确定了隶属于各个类型的主要栽培品种。通过对每一类型的种核重、核形指数及种仁中干物质、直链淀粉、支链淀粉、淀粉、粗蛋白、可溶性糖、氢氰酸含量的分析 ,对种核品质作了鉴评 ,为银杏核用品种资源的利用和改良提供了依据。     

筇竹种子特性及实生苗生长发育规律的研究

本文对筇竹种子特性和实生苗的生长发育规律进行了系统研究。结果表明 :1筇竹的种子长 1.0 4～ 1.4 5 cm ,直径为 0 .6 9～ 1.14cm:种子净度为 92 .2 6 %、千粒重 5 0 2 .95 g、发芽率 92 %、含水量达 70 .18% ;种子休眠期短、不耐贮藏 ;2二年生实生苗高 39.38cm、地径 0 .2 8cm、竹鞭长 39.38cm ,根系发达 ,分蘖能力强 ,笋芽多达 15个 /丛 ,可在秋季出圃造林 ;3天然更新差、竹苗生长不良是筇竹濒危的原因之一。     

日本落叶松种子园种用价值测试初析

对我国６个主要日本落叶松种子园种用价值测验的结果表明，各地种子园的遗传品质差异显著。种用价值大小排序为：天麻＞桓仁＞清凉山＞白旗寨＞赤峰＞大孤家＞对照。初选出遗传品质较高的天麻、桓仁和清凉山种子园，６年生（连苗期）幼林树高、胸径、材积生长量可分别获得８４％—１１０％、１２７％—２６７％、２６９％—６６３％的遗传增益。白旗寨、赤峰和大孤家３个种子园虽有一定改良效果，但都低于总平均水平，并与对照差异不显著。研究结果对豫西地区引种和推行种子园种子造林有重要指导作用对我国６个主要日本落叶松种子园种用价值测验的结果表明，各地种子园的遗传品质差异显著。种用价值大小排序为：天麻＞桓仁＞清凉山＞白旗寨＞赤峰＞大孤家＞对照。初选出遗传品质较高的天麻、桓仁和清凉山种子园，６年生（连苗期）幼林树高、胸径、材积生长量可分别获得８４％—１１０％、１２７％—２６７％、２６９％—６６３％的遗传增益。白旗寨、赤峰和大孤家３个种子园虽有一定改良效果，但都低于总平均水平，并与对照差异不显著。研究结果对豫西地区引种和推行种子园种子造林有重要指导作用     

林木种苗质量检测的现状与对策

种苗检测是评定林木种苗质量的重要手段 ,根据《种子法》及新标准对种苗检测的要求 ,在分析种苗检测现状与存在问题的基础上 ,提出种苗检测的调整思路     

Nursery soil cover influences germination of Thujopsis dolabrata var. hondai seeds

We examined the influence of nursery soil cover on germination of Thujopsis dolabrata var. hondai. Seeds were sown under seeding bed conditions: (1) nursery soil (andosol) without soil cover, (2) Kanuma pumice without soil cover, (3) nursery soil with nursery soil cover, and (4) nursery soil with sterilized sand cover. Germination percentages were compared between these conditions. The germination percentage (8.8%) at 10 weeks after sowing under condition 3 was significantly lower than under conditions 1, 2, and 4 (56.8%, 52.0%, and 47.2%, respectively). Of the nongerminated seeds under condition 3, 75.0% were decayed and several fungi were isolated from decayed seeds. An inoculation test of isolated fungi Cylindrocarpon tenue, Cylindrocarpon sp., Fusarium oxysporum, and Botrytis sp. to seeds showed that these fungi caused seed decay. Our results indicated that nursery soil cover may not be suitable for T. dolabrata var. hondai seeds sown in nursery soil because of seed decay by pathogens.     

油松种子园无性系球果与种子性状变异的初步研究

研究了３２个油松无性系的球果与种子的性状变异，初步了解到种子园各无性系的种子品质，分析了球果与种子之间的性状相关性，为油松优良无性系的选择和初级种子园留优去劣疏伐提供了参考。     

香椿种子发芽率测定方法的研究

测定香椿种子发芽率有物理，生理，生化等方法。用直观法，红四氮唑（TTC）染色法，蓝墨水染色法，导电法，吸胀状态测定法对香椿种子的发芽率进行了测定研究，结果表明：用TTC，蓝墨水染色法测定香椿种子的发芽率，测定迅速，方法简便，容易掌握，结果可靠，是较为理想的测定方法，值得推广。     

The propagation of Ramón (Brosimum alicastrum Sw.; Moraceae) in Mayan homegardens of the Yucatan peninsula of Mexico

In the Yucatan peninsula of Mexico, Maya natives have been propagating important species for centuries. However, little documentation exists of these methods, and traditional knowledge is fading as younger generations seek work in urban centers. With growing interest in using some of these species for plantation-scale production, this knowledge should be captured to aid in propagation and cultural methods of selected species. One such species, Ramón (Brosimum alicastrum Sw.), is grown in Mayan homegardens primarily as a source of dry season forage. We conducted a survey of Mayan families in several municipalities to determine basic propagation habits and procedures for cultivating Ramón, and used this information to conduct some controlled-environment studies of reproductive ecology of the species. Our survey showed that all or most Maya grow the Ramón tree in homegardens for forage and that the tree is both cultivated from wild seedlings as well as planted on a small scale. Propagation is by seed and young seedlings are irrigated until they are established. We examined the effects of temperature on seed germination and found that maximum germination occurred between 27° and 38 °C, with best germination and growth of healthy seedlings at 33 °C. No germination occurred below 21° or above 44 °C. Simulated Maya irrigation gave a four-fold increase in growth rate of seedlings, aiding early establishment. Watering gave seedlings of greater biomass, greater stem and root length, and greater numbers and size of leaves. This magnitude of response may provide an economic return for plantation culture of Ramón for forage production.     

Petroleum flotation technique upgrades the germinability of <Emphasis Type="Italic">Casuarina equisetifolia</Emphasis> seed lots

The germination of Casuarina equisetifolia Forst seed lots is low (40–50%) even when freshly collected. This study aimed at upgrading the germination performance by removing non-germinable seeds using petroleum flotation technique. Seeds collected from 19 individual trees in seedling seed orchards in India were assessed using X-ray to determine the proportion of different seed lot fractions. The feasibility of petroleum ether as a separation medium was tested. Morphological characters of floating and sunken seeds were further studied using image analysis technique to examine their effects on the separation efficiency. The X-ray analysis revealed a large quantity of shrivelled, empty and insect-damaged seeds, altogether accounting 50%, which were the causes of low percentage germination of un-graded seed lots (48%). Petroleum flotation resulted in 90% germination in the sunken fraction and 4% in the floating fraction. The separation was distinct for most seed lots, except few seed lots that had relatively low germination in the sunken fractions and more than 10% germination in the floating fractions. As a whole, petroleum flotation appears to be a feasible technique to upgrade the germination of C. equisetifolia seed lots, and its efficacy is influenced by wing surface area, seed density and wing quotient of filled and empty seeds.     

Explaining variation in Brazil nut fruit production

Brazil nut is widely recognized as the cornerstone of the Amazonian extractive economy. Tight linkages between Brazil nut production, regional income, and intact mature forests have thrust this species into focus as a key component of Amazonian conservation and income generation strategies. Nonetheless, a comprehensive synthesis of factors explaining Brazil nut fruit production variation is lacking. We aimed to address this knowledge gap, asking: (1) What are the rates and annual variation of Bertholletia excelsa fruit production at individual and population levels? (2) What factors explain B. excelsa production variation, focusing on spatial and temporal variables, diameter at breast height (dbh), crown attributes, liana loads, and soil attributes? and (3) Does liana cutting affect fruit production?