南宁青秀山荫生植物普查及其耐荫性研究初探

指出了青秀山景区绿化中应充分美化景区的每一个区域,增加景观的层次和色彩。由于林下光线不足植物品种耐荫能力各不相同,如何配置既能适合林木郁闭度,又能满足景观的要求,没有一个比较明确的量化标准,原有生产中耐荫植物的选择种植中依靠生产中的经验判断,使一些植物对小环境郁闭度无法适用,出现生长不良、逐渐死亡等问题,造成了重复施工和不必要的资源浪费。对青秀山中现有的荫生植物进行了较全面调查研究,总结了青秀山荫生植物的种植后生长现状,对荫生植物的耐荫性进行了初步了解,为对荫生植物耐荫性的进一步研究奠定基础。     

秃杉引种耐荫性的初步研究

在江苏南京、江宁、句容等地对引种秃杉的耐荫性初步研究表明,秃杉幼龄阶段具有较强的耐荫性。苗期可以适应200～300勒克司的微弱光照,幼树枝叶在500～1000勒克司弱光照下的树冠内,仍能正常生长。适度遮荫可以提高裸根苗移植成活率,避免或减少日灼造成的生理病害,并促进苗木生长。利用这一重要生物学特性对于在纬度偏北、海拔低、光照强的江苏引种区选择合理的秃杉引种栽培模式,保障引种顺利进行,扩大和保存繁衍秃杉珍稀树种资源具有重要实践意义。     

园林植物的耐荫性研究

本研究选取５０种园林植物,培养在相同条件下,对其叶绿素含量、叶绿素ａ／ｂ值、光补偿点及光饱和点进行了测定,并依据其对应于光通量密度梯度的净光合速率绘制光反应曲线,试图探寻植物耐荫性与光合作用的相关规律     

红松耐荫性研究综述

红松作为阔叶红松林的优势树种之一,一直受到人们的关注,文中阐述了红松耐荫性研究的意义及国内外研究现状,介绍了几种研究红松耐荫性的方法,结果均表明,红松在其幼苗时期具有一定的耐荫性.同时,指出了红松耐荫性研究中缺少耐荫性的评价指标体系和我国在红松耐荫性研究方面存在的问题.     

秃杉引种耐荫性的初步探讨

在江苏南京市南郊对引种秃杉的耐荫性初步探讨表明,秃杉幼龄阶段具有较强的耐荫性,苗期可以适应200—300勒克司的微弱光照;幼树枝叶在500—1000勒克司弱光照下的树冠内,仍能正常生长。适度遮荫可以提高裸根苗移植成活率,避免或减少日灼造成的生理病害,并促进苗木生长。利用这一重要生物学特性对于在纬度偏北、海拔低、光照强的江苏引种区选择合理的秃杉引种栽培模式,保障引种顺利进行,扩大和保存繁衍秃杉珍稀树种资源具有重要实践意义.     

熊掌木等3种植物耐荫性的比较研究

通过对上海市崇明岛上熊掌木、八角金盘、常春藤3种耐荫植物的叶片气孔密度和解剖结构的比较研究,结果表明:(1)叶绿素a含量大小序列为八角金盘>常春藤>熊掌木;叶绿素b含量大小序列为八角金盘>常春藤>熊掌木;叶绿素a/b值大小序列为熊掌木>常春藤>八角金盘;叶绿素(a+b)含量的大小序列为八角金盘>常春藤>熊掌木;3种植物海绵组织的厚度大小顺序是八角金盘、常春藤、熊掌木,最终推断出三者耐荫性大小顺序依次是八角金盘、常春藤、熊掌木。(2)3种耐荫植物气孔大小顺序为熊掌木>八角金盘>常春藤;3种耐荫植物气孔密度的大小顺序为常春藤>八角金盘>熊掌木,与耐荫性之间无明显的规律性。     

13种绿墙植物的耐荫性研究

为筛选适用于光照较弱的绿墙植物,提高绿墙观赏期,研究了13种广州市常用绿墙植物的叶厚度、叶面积、叶绿素a/b和外观形态等指标,评价其耐荫性。综合分析研究结果,得到13种植物的耐荫性,由强到弱为:孔雀竹芋波士顿蕨络石鹅掌藤彩虹竹芋红背桂肾蕨吊兰天门冬山菅兰红花檵木花叶小蜡红边龙血树。研究表明大部分植物适宜作为绿墙植物,尤其是孔雀竹芋、波士顿蕨、络石、鹅掌藤,只有吊兰、花叶小蜡不适宜作为绿墙植物。     

青檀耐荫性的初步研究

在连续３年测定比较几个不同树种的生理特性和树冠结构的基础上，本文对青檀的耐荫性进行了初步分析，结果表明，青檀的耐荫性随年龄的增大而降低，１２年生以前，青檀是耐荫的；１３至２５年生之间，青檀是喜光树种；２６年生以后青檀则逐渐变为阳性树种。比较的结果还表明，青檀的耐荫性较马尾松强，较杉木弱，从总体看属中偏阳树种。     

植物耐荫性研究进展

植物为适应荫蔽的环境，导致在叶片形态，解剖构造，叶绿体结构与运动，光合色素含量及光量子产额，光合作用单位，电子传递等方面产生变化或特化，以保证在弱光量子照射条件下仍能充分利用光能，维持生长所需的能量平衡，进行正常的生命活动。     

矮滨菊的耐荫性研究

为了研究矮滨菊的耐荫性,进行了30%、50%、70%、90%4个梯度的遮荫处理,以全光照处理作为对照,观察矮滨菊在4种处理下的形态指标、光合指标的变化。结果表明:矮滨菊在遮荫度为30%时形态的数值都要明显高于其他3个处理时的数值,50%时光合的数值要明显高于其他3个处理。因此认为矮滨菊具有一定的适应弱光环境的能力,在遮荫度为30%~50%的环境下生长良好。     

长春蔓组培生产中污染菌的防除

长春蔓（Ｖｉｎｃａ ｍ ａｊｏｒｃｖ．Ｖａｒｉｅｇａｔａ）是优良的盆栽观叶植物,用组培方法生产母本苗,易遭大量真、细菌的污染。该文研究了对污染的防除方法和不同抗菌素对内生菌（Ｘａｎｔｈｏｍｏｎａｓｓｐ．）的作用。结果表明：初代培养的消毒程序以７０％ 酒精＋ ０．１％ 升汞为好。为防治细菌的抗药性可以同时使用二种抗菌素。链霉素２０ｍ ｇｌ－ １ ＋ 头孢唑林钠３０ｍ ｇｌ－ １的配方能将内生菌的污染率控制在４０％ 以下。     

遮光处理下4种姜科Zingiberaceae植物叶绿素荧光特性综合评价

为了研究不同光照强度对姜科植物叶片叶绿素荧光参数的影响,以益智Alpinia oxyphylla、花叶山姜A.pumila、红柄郁金Curcuma rubescens和花叶艳山姜A. zerumbet ‘Variegata’4种姜科植物为试验材料,在不同遮光处理下测定姜科植物叶片的最大光化学效率Fv/Fm、非光化学淬灭NPQ、实际光能转化效率Y(Ⅱ),光化学淬灭系数qP和表观电子传递速率ETR,综合评价结果显示:4种姜科植物的耐阴性为花叶山姜>花叶艳山姜>益智>红柄郁金。     

耐荫植物耐寒性的观测研究

从广州等地引进77种耐荫植物，冬季放置在塑料大棚或室内，观察其对低温的适应性，从而得出耐荫植物的耐荫性，为耐荫植物北移及开发提供依据。     

4种灌木树种的耐荫性研究

以进入城市园林绿化树种行列的大花溲疏、荆条、蚂蚱腿子、小桐子4种喜光灌木树种为对象,研究其耐荫性能。对此4种植物进行不同程度的遮荫处理后,测定其叶片的光合作用、呼吸作用及其相关生理指标的变化,比较了遮荫对此4种喜光灌木树种所造成的一些生理变化,并对这4种喜光灌木树种耐荫性的强弱进行了综合排序。研究发现,遮荫对此4种灌木树种的光合特性等生理指标都有不同程度的影响,其耐荫性的综合排序结果为:蚂蚱腿子的耐荫性最强,大花溲疏次之,再次是小桐子,而荆条的耐荫性最弱。     

10种地被植物的耐阴性比较研究

在自然遮荫条件下,比较研究了10种地被植物的耐阴性。结果表明:"八宝景天"、"松塔景天"和"小叶扶芳藤"最耐阴",大花滨菊"、"北京小菊"、"北美黄"、"鸢尾"和"德国景天"的较耐阴,而"金娃娃萱草"和"胭脂红景天"不耐阴。     

小蔓长春花离体快繁技术

以小蔓长春花嫩枝的茎段和茎尖为外植体,经90天的增殖培养试验表明,最适宜的增殖培养基为MS 6-BA 0.8~1.2 mg.L-1 IBA 0.2~0.4 mg.L-1,诱导生根的最佳培养基为1/2MS IBA0.1~0.5 mg.L-1,生根率为96.3%~100%。瓶外生根试验结果表明,用1 000~1 200 mg.L-1IBA蘸根,生根率达81%。     

Effects of light availability and soil flooding on growth and photosynthetic characteristics of Genipa americana L. seedlings

Genipa americana L. (Rubiaceae) is a late successional neotropical fruit tree used in riparian forest restoration programs. We analyze the effects of light availability and soil flooding on the growth and photosynthetic characteristics of G. americana seedlings under nursery and natural light conditions. Two light levels (full sunlight and shade), and two levels of soil water (flooded and control) were used in the experiment. Flooding induced significant changes in the total seedling biomass (P < 0.01). The differences among water treatments were 70 and 10% at full sunlight and shade, respectively. These changes were explained by alterations in the maximum quantum efficiency of the photosystem 2 (Fv/Fm), light-saturated net photosynthetic rates (A _sat) and intrinsic water use efficiency (WUE). G. americana has high physiological plasticity in relation to the light availability and flooding, although significant interactive effects between high light exposure and soil flooding were observed in several photosynthetic and growth variables. The results highlight the importance of the synergistic effects between physical environmental variables on the establishment and growth of G. americana seedlings. In the practical point of view we can indicate that, in degraded riparian forests subjected to soil flooding, seedlings of this species should be planted under partially shaded environments.     

Is light the key factor for success of tube shelters in forest restoration plantings under Mediterranean climates?

Tube shelters were designed to protect against browsing, but they improve seedling survival in Mediterranean dry climates. Mechanisms for this response, however, are not fully understood and this knowledge can be useful to help design optimal tube shelters for Mediterranean species and climates. Our objective in this study was to determine if the positive effect of tube shelters is due to enhanced growth during the wet season or to reduced light stress during the dry season. We performed two independent experiments. In the first, we assessed root growth during the wet season in two Mediterranean species with contrasting light tolerance (Quercus ilex L. and Pinus halepensis Mill.) growing in tubes with varying light transmissivity. In the second experiment, we studied the response of a Quercus ilex plantation to different shelter treatments. Root growth during the wet season was reduced with decreasing light transmissivity in the shade intolerant P. halepensis, but not in the shade tolerant Quercus ilex. Survival of Q. ilex shaded by a mesh shelter only during summer was higher than in unsheltered seedlings and similar to the survival in tube and mesh shelters during the whole season. This suggests that shade during the dry period was the main factor explaining survival in this species. This effect could be related to the lower leaf temperature recorded in sheltered seedlings. We conclude that Q. ilex (and perhaps other late successional, shade tolerant Mediterranean species) should be planted in tubes with the currently used light transmissivity because these shelters reduce light stress in summer without impairing root growth in the wet season. However, current tubes impair root growth in P. halepensis (and likely other pioneer, shade intolerant Mediterranean species), so higher transmissivity tubes may be necessary. Optimal transmissivity for tube shelter in Mediterranean climates is species-specific and identifiable as the point that minimizes light stress during summer without impairing root growth in the wet season.