6个沿海防护林树种冻害调查与分析

对临海市6种平原防护林树种在最低温度降至-7℃时的受冻害情况进行了实地调查,并按照冻害程度进行了分级。通过计算树种冻害指数,6种植物的冻害程度由重到轻的顺序为:乌桕红叶石楠木麻黄舟山红楠华棕夹竹桃,夹竹桃基本无冻害发生;66.67%乌桕全部冻死,受冻害最严重。通过此次防护林树种冻害调查与分析,可为今后台州地区防护林植物种类选择、应用养护提供重要依据。     

2016年丽水学院校园植物冻害调查与分析

2016年1月,丽水出现了历史上罕见的严寒天气,同年2月和6月,分别对丽水学院校园内的主要常绿木本植物和竹类植物的冻害情况进行了调查,结果表明:在所调查的30种植物中,受冻害的植物有7种,占比23.7％,未受冻的植物23种,占76.3％;计算植物冻害指数,表明7种受冻害植物的冻害程度从重到轻的顺序为白兰花＞绿竹＞孝顺竹＞苏铁＞温州水竹＞夹竹桃＞樟树,其中白兰花全部冻死.     

长春市主要绿化树种适应低温冻害能力的调查与分析

以长春市部分绿地的主要园林绿化树种为对象,对其适应低温冻害的能力进行了调查与分析,结果表明:在2009～2010年冬春季节持续低温作用下,12种外来树种中未遭受冻害的有青杄等7种,占58.3%;油松、丹东桧柏、大径级垂榆、京桃、刺槐普遍遭受冻害,都有死亡植株发生,其中大径级垂榆冻死率高达63.6%。低温累积效应是导致树木遭受冻害的主要因素,种间的遗传差异亦是因素之一。乡土野生树种无冻害相发生。     

南京地区浙江楠苗期冻害调查研究

对南京地区引进的浙江楠苗木冻害进行了调查。结果表明，播种密度不同，苗木受害程度不同，当播种密度为80，160，200，240粒／m^2时，苗木遭受重度冻害（Ⅳ＋V）的比率分别为1．96％，4．05％，4．96％，1．45％，冻害指数分别为0．21，0．29，0．22，0．16。1年生苗遭受冻害的程度较重，而2年生苗遭受冻害的程度较轻；在遮荫处理后，苗木抗寒力减弱。1层遮荫与全光处理苗木的重度冻害（Ⅳ＋Ⅴ）比率相差不大，而2层遮荫和3层遮荫处理后，苗木重度冻害（Ⅳ＋Ⅴ）比率与不遮荫相比有较大的差异。移植苗木的抗寒性减弱。移植苗木重度冻害（Ⅳ＋Ⅴ）比率普遍高于留床苗木重度冻害（Ⅳ＋Ⅴ）比率。     

经济林冻害调查及其防冻措施

对江西1991年冬季经济林冻害情况进行了调查,比较了各树种、品种的抗冻能力,并分析了地形地势、经营管理水平等因素对冻害的影响,依此指出了防冻措施。     

2015～2016年冬春武汉植物园61种樟科植物冻害调查

针对2016年1月的极端低温天气,对武汉植物园61种露天栽培的樟科植物受冻害情况进行了调查。结果表明:538株樟科植物中,受冻害85株,占所有调查植株15.8%;冻害程度达到Ⅱ级以上的有11个种,占所有调查樟科种类的18.0%;本次调查中,新木姜子属和楠木属耐寒性较好,而木姜子属的耐寒性整体表现最差,以上调查结果为樟科植物在武汉市的园林应用提供了科学依据。     

绵阳引种的五种棕榈科植物冻害调查分析

对绵阳市5种棕榈科植物进行冻害情况调查研究的结果表明:在市区,加拿利海枣、银海枣、华盛顿棕榈和蒲葵冻害不明显,皇后葵有1~3级冻害;在郊区,5种棕榈科植物都出现了严重冻害。棕榈科植物发生冻害的轻重受树种、树龄、苗源、地形地势、植物群落结构、栽培管理和防冻措施等因素影响。     

昆明市绿化树种冻害情况调查

2014年选择5条线路,对昆明市各县区街道及高速公路28个常见绿化树种的生长及冻害情况进行调查,结合冻害症状,制定冻害标准,确定冻害等级。结果表明,28种绿化树种中,无冻害植株为3 842株,占51.81%;轻度冻害植株为1 424株,占19.2%;中度冻害植株为960株,占12.95%;重度冻害植株为531株,占7.16%;特重度冻害植株为388株,占5.23%。小叶榕、鸭掌木、银桦、凤凰木、蓝桉、圣诞树受害严重,极度不适应冻害天气。而云南松、华山松、麻栎、青冈、川滇桤木、园柏则受害轻微,表现出对冻害极好的抗性。在地势低洼、地形闭塞的小盆地、低洼地、坡地下部,冷空气容易沉积,受害比较严重;山坡中部,空气流动畅通,受冻较轻;山头或者地势平坦风口处由于直接受寒风吹袭,受害比较严重。     

乐昌市园林植物冻害调查与分析

调查了经历乐昌市2020年12月—2021年1月低温天气的园林植物的受冻害、需处理和恢复的情况,记录到受冻害的园林植物有124种（含杂交种、变型和园艺品种）,具有受冻害种类较多、外来植物受冻害比例高和同种植物受冻害程度因地或苗而异的特点。受冻害的主要原因除了长时间的低温天气外,还有苗木栽培时间短、引种不科学、管理粗放等。建议遵循适地适树原则,科学选择植物种类,区别选择南北两地种类;尽量使用本地苗圃培育的苗木,少用外来苗木;加强人工管护和灾后处理;提前炼苗。     

南充市小叶榕冻害情况的调查研究——以西华师范大学为例

本研究为更深入了解小叶榕受冻害的总体情况,耐受度,影响因素,探寻环境因素和树木胸径与小叶榕冻害程度之间的关系,以便改进和调整栽培养护措施,提升校园乃至整个城市的绿化工作。首先对树木大小进行分级,实地调查小叶榕受冻害的情况,观测记录树冠受冻面积,小叶榕冻害情况初步定级,对小叶榕生长环境进行描述,包括有无建筑遮挡,建筑朝向,通风条件等。观测冻害植株百分率,计算病情指数,观测其最大耐受限度;通过分析建筑背风面和迎风面小叶榕冻害程度,和周围有无建筑遮挡小叶榕冻害程度,探究区域小环境与小叶榕冻害严重度的关系。分析树木胸径与小叶榕冻害程度的关系。结果显示,调查范围内小叶榕受冻害范围100%,冻害指数综合为56.94%,属于重度冻害,冻害耐受度5级,并且通过数据分析发现区域小环境对小叶榕冻害程度有显著影响,树木胸径对小叶榕冻害无显著影响。最后根据实际情况提出防治建议。     

梧州市外来入侵植物调查研究

通过实地调查与文献查询相结合的方法,确认分析梧州市外来入侵植物种类、性状、起源地、传入途径和危害程度,结果表明：梧州市目前共有入侵植物27种,隶属于14科25属,其中以菊科植物种类最多,占总种数29．63％;草本植物20种占绝对优势,占总种数74．07％;24种起源地为美洲,占总种数88．89％;有意引种数量比例超过总种数一半;危害程度达到严重和较严重比例不高,少于总种数的1／4。目前梧州市入侵植物尚未引发严重的生态系统破坏问题,但存在较多潜在的生态安全隐患。最后对梧州市外来入侵植物的管理提出建议。     

特大冰冻雪灾后长沙市竹类的冻害状况

2008年1月中旬至2月初,我国南方遭受了1954年以来最严重的低温冰雪灾害.对冰雪灾害后长沙市75种(含变种、变型和栽培变种)竹类的冻害程度进行调查,并于同年4月调查气温回升后冻害竹类的恢复生长情况.依据竹类的冻害等级和竹类的3种地下茎类型,对不同地下茎类型中竹子的冻害状况进行统计分析研究.结果表明:1)冻害程度为Ⅰ,Ⅱ,Ⅲ和Ⅳ级的竹子分别有2,10,24和34种(含变种、变型和栽培变种),未受冻害的竹种有茶秆竹、刚竹、红哺鸡竹、湘妃竹和爬地竹;2)所有Ⅰ级冻害的种类及70%的Ⅱ级冻害种类为合轴型,80%的未受冻害种类为单轴型;3)在合轴型的竹类中,属Ⅰ,Ⅱ和Ⅲ级冻害的种数分别为该类型总种数的10.5%,36.8%和47.4%,而复轴型与单轴型的竹类中均无Ⅰ级冻害的种类,前者以Ⅳ级冻害为主,后者以Ⅲ和Ⅳ级冻害为主,单轴型的竹类中无冻害的种类高达该类型总种数的11.8%,全市所有竹子中合轴型竹类的冻害程度最重,单轴型竹类的冻害程度最轻.     

Effects of simulated thaw on xylem cavitation,residual embolism,spring dieback and shoot growth in yellow birch

Yellow birch seedlings (Betula alleghaniensis Britt.) that had lost more than 90% of their stem hydraulic conductivity during ambient winter temperatures were exposed to 0 and 20 days of a simulated winter thaw followed by a 48-h freezing treatment at 0, -5, -10, -20 and -30 degrees C. After measuring freezing injury to shoots and roots, the seedlings were placed in a greenhouse where recovery of xylem conductivity and new growth were measured. Shoot xylem cavitation was measured as percent loss of hydraulic conductivity. Shoot freezing injury was assessed by electrolyte leakage (EL) and root freezing injury was assessed by EL and triphenyl tetrazolium chloride reduction. Seedlings pretreated with thaw had higher stem water contents and suffered more freezing damage to roots and shoots (at -20 and -30 degrees C, respectively) than unthawed seedlings. After 3 weeks in a greenhouse, seedlings from the 0, -5 and -10 degrees C freezing treatments showed complete recovery of xylem conductivity, with substantially increased stem water contents. Poor recovery of hydraulic conductivity was observed only in seedlings that were subjected to freezing treatments at -20 and -30 degrees C, regardless of thaw treatment. Of these embolized seedlings, however, only those not previously thawed showed recovery of hydraulic conductivity or regained stem water content after 9 weeks in the greenhouse. Shoot dieback, bud burst and length of new shoots were significantly related to the extent of stem xylem cavitation and freezing injury. We conclude that (1) the simulated winter thaw predisposed yellow birch seedlings to freezing damage in shoots and roots by dehardening tissues and increasing their water content; (2) root freezing damage in turn affected the seedlings' ability to refill embolized stem xylem, resulting in considerable residual xylem embolism after spring refilling; (3) further recovery of stem xylem conductivity was attributable to growth of new vessels; (4) and the permanent residual embolism, together with root and shoot freezing injury, caused increased dieback, bud mortality and reduced growth of new shoots.     

南宁苗圃园林植物寒冻害调查分析及预防对策

本文以南宁市嘉和城苗圃为对象,通过对植物外部形态进行感观鉴定,对植物的叶、芽、枝、整株等的生长指标、组织褐变等进行观察,把园林植物受寒冻害程度划分为五个等级,然后根据等级评价标准,对2011年苗圃园林植物受寒冻害情况进行调查与数据收集分析。结果表明,持续低温给苗圃园林植物造成明显寒冻害,热带植物种类抗寒性差,受寒冻害严重,甚至整株死亡,多为IV-V级。合理选择植物品种、做好寒冻害来之前的防寒措施和植物受冻后的及时补救措施是避免园林植物大面积受寒冻害的关键措施。     

保山市核桃幼树冻害成因及防治技术措施

在实践和调查研究基础上,论述保山市核桃幼树冻害发生发展规律、冻害症状及危害程度,认为冻害的主要成因是低温或降霜降雪,干旱、栽培管理措施及选择栽培品种不当会加剧冻害发生的程度.藉此提出了预防核桃幼树冻害和处理冻害植株的技术措施.     

寒害天气对永州市赤桉组培苗造林的影响

2004年冬季永州市经历了严重的寒害天气。灾害过后,调查了东安县种植的赤桉组培苗受冻和冻后恢复情况,分析比较了赤桉组培苗种植后的耐寒性和冻后恢复能力。调查结果表明：2004年冬季是永州市罕见的寒害天气,所有引种的桉树幼林均受到不同程度的冻害,但赤桉组培苗幼林受冻程度较轻,冻后恢复较快,类似2004年冬季的寒害天气,对永州市赤桉组培苗造林没有影响。根据永州南桉北移造林的现状,提出了发展桉树产业的建议。     

10个木兰科树种北移引种试验初报

对10种木兰科树种进行北移引种试验,比较不同树种在我国北亚热带和暖温带过渡地区河南省西南部的适应性及引种潜力。采用1～2 a生容器苗和地栽苗移栽,按常规水肥管理,并观测苗期在极端气候条件下的旱害和冻害等适应性状指标。结果表明,除观光木外,其余都能适应河南西南部的气候条件,生长基本正常,部分树种已开花结果。在-3℃～-4℃气温下,观光木受冻率达100%,冻害指数为V级,苗木地上部分冻死。1年生红花木莲,由于苗较小,受冻率为5%～30%,冻害指数I～II级,部分叶片受害。在持续秋旱60天的极端干旱气候条件下,采用每天人工早晚浇水一次,引种成活的9种木兰科植物均具有较强的抗旱适应性,受害率不到1%,仅有极少数植株发生枯梢受害。     

Root cold tolerance of black spruce seedlings: viability tests in relation to survival and regrowth

Root systems of 6-month-old, cold-hardened, container-grown black spruce seedlings (Picea mariana (Mill.) B.S.P.) were exposed to 0, -5, -10, -15, -20, or -22.5 degrees C. Freezing-induced damage to fine roots, coarse roots and the whole root system was assessed by various viability tests including leakage of electrolytes, leakage of phenolic compounds, water loss, root and shoot water potentials, and live root dry mass. To assess the long-term effects of freezing-induced root damage, seedling survival and regrowth were measured. Leakage of both electrolytes and phenolic compounds differed among fine roots, coarse roots, and whole root systems. In coarse roots and the whole root system, but not in fine roots, leakage of electrolytes, leakage of phenolic compounds, water loss, and root and shoot water potentials were correlated with percentage of live root dry mass which, in turn, was highly correlated with seedling survival and regrowth. Compared with live root dry mass, electrolyte and phenolic leakage, water loss, and root and shoot water potentials were less well correlated with seedling survival and regrowth. Among the viability tests, electrolyte leakage of the whole root system correlated most closely with seedling survival and regrowth. Under freezing conditions that destroyed less than 50% of each seedling's root system, about 70% of the seedlings survived and subsequent growth was little affected, whereas under freezing conditions that destroyed 70% of each seedling's root system, only about 30% of the seedlings survived and subsequent growth was reduced compared with that of undamaged plants.     

Chlorophyll fluorescence and variations in tissue cold hardiness in response to freezing stress in Douglas-fir seedlings

Two-year-old coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings from two seed lots were exposed to controlled freezing temperatures every 4 weeks from October 1993 through April 1994. Freezing effects were assessed by measuring chlorophyll fluorescence emissions 1 day after freezing and by evaluating damage to the bud, cambium, and needle tissues 7 days after freezing. Differences between the seed lots as well as changes in cold hardiness among the bud, cambium, and needle tissues were evident throughout the duration of the study. Tissue damage was higher with increased freezing stress. Severity of damage to each of the tissues varied seasonally. Chlorophyll fluorescence emissions were lower with higher freezing stress (except during November and December, when test temperatures were not low enough to significantly damage the seedlings) and showed a strong relationship with morphological assessments of freezing stress. The slope of the slow kinetics phase of the chlorophyll fluorescence curve tended to be less steep (i.e., quenching was reduced) with higher freezing stress. Nonfrozen chlorophyll fluorescence measurements showed no obvious relationship with LT₅₀ for either seed lot. However, chlorophyll fluorescence measurements are useful for determining cold hardiness and resistance to stress, because they provide a rapid assessment of seedling vigor following exposure to freezing.