万寿菊9个品种高温半致死温度与耐热性研究

对万寿菊9个品种叶片进行不同的高温处理后,测定其叶片相对电导率,通过Logistic方程拟合,计算出各自的高温半致死温度,以评价其耐热性。结果表明,9个品种耐热性由强到弱排序依次为‘金门’、‘拳王’、‘发现’、‘巨人’、‘珍妮’、‘小英雄’、‘迪阿哥’、‘鸿运’、‘大英雄’。该结果与田间试验观测基本一致,说明高温半致死温度可以作为万寿菊品种耐热性评价的重要指标之一。     

应用Logistic方程确定三种桉树的低温半致死温度

以3种桉树幼苗叶片为实验材料,以电导法测定低温胁迫下其叶片的电导率变化并配以Logistic方程进行回归分析,发现不同低温下的电导率遵循Logistic方程的变化规律,且与半致死温度呈线性关系,依据回归方程计算得到尾叶桉(E.urophylla)、巨桉(E.grandis)和邓恩桉(E.dunnii)的拐点半致死温度分别为-4.53℃、-8.12℃、-7.79℃.     

濒危树种越南青冈的半致死温度研究

越南青冈为壳斗科濒危树种。通过越南青冈2年生温室容器苗叶片和茎段分别在9个高温和8个低温温度处理后,测定其电解质渗出率,利用Logistic方程计算其高温、低温的半致死温度（ LT50）。结果表明,叶片和枝条组织的电解质渗出率与处理温度之间均呈“S”型曲线, Logistic方程拟合度较高;计算得到越南青冈2年生苗木叶片的高温、低温半致死温度分别为42.04℃和-1.78℃,茎段的高温、低温半致死温度分别为46.62℃和-9.72℃。研究结果可推测越南青冈的潜在地理分布区,为该濒危树种的人工栽培、就地或迁地保护提供依据。     

４种珍稀濒危植物的半致死温度研究

以红皮糙果茶（Camellia crapnelliana）、伯乐树（Bretschneidera sinensis）、金花茶（C．petelotii）、坡垒（Hopea hainanensis）4种珍稀濒危植物1 a 生幼苗的成熟叶片为试验材料,进行高温、低温胁迫试验,测定叶片相对电导率,并利用 Logistic 方程建立回归模型,计算出高温和低温半致死温度。结果表明：在高温胁迫和低温胁迫过程中,相对电导率变化趋势均呈现明显的“S”型曲线,耐热性大小顺序依次为：金花茶＞红皮糙果茶＞坡垒＞伯乐树,高温半致死温度在41．6～46．3℃之间;耐寒性大小顺序依次为：红皮糙果茶＞坡垒＞伯乐树＞金花茶,其低温半致死温度在－7．19～－6．16℃之间。供试的4种珍稀濒危植物1 a 生苗均具有较强的耐热性和耐寒性,在广州地区可以安全露地越夏及越冬。研究结果可推测这4种珍稀濒危植物潜在的适应地区,从而扩大引种栽培。     

香花油茶的园林应用

介绍香花油茶(Camellia osmantha Ye CX,Ma JL et Ye H)的生长习性、形态特征以及其观赏特性,探讨香花油茶在园林绿化中的应用模式,并对其园林应用前景进行了展望。     

香花油茶分子分类与鉴定

为给香花油茶归类地位的确认提供一定的分子依据,明确香花油茶的分类地位,通过ISSR标记技术,探究香花油茶与山茶属中形态特征相似的其它5个种之间的亲缘关系。结果表明:香花油茶与供试山茶属5个种(小果油茶、南荣油茶、窄叶短柱茶、普通油茶、攸县油茶)遗传距离较远,各自聚类显著,因此香花油茶不属于参试的5个山茶物种;其中与窄叶短柱茶的亲缘关系为近,遗传距离偏小,但遗传距离也远大于种内差异,且形态特征与窄叶短柱茶最为接近,推测香花油茶可能是山茶属短柱茶组1个新物种。     

取样部位、时间对植物高温半致死温度的影响

为了分析取样部位、时间对木本植物高温半致死温度的影响,选取桂树、松树、柏树、冬青4种常绿植物的叶片、1年生枝条、2年生枝条作为试验材料,分别于2017年8月、10月、12月以及2018年2月运用电导率法和Logistic方程对其进行高温半致死温度的测定及分析,并根据高温半致死温度高低进行耐热性强弱排列。试验结果表明,4种常绿植物的耐热性强弱顺序依次为松树>柏树>冬青>桂树;对于同一植物的不同取样部位来说,其耐热性强弱顺序依次为2年生枝条>1年生枝条>叶片;对于同一植物的相同取样部位来说,取样时间对其耐热性的强弱影响不大。     

海南油茶叶片解剖结构与耐热性比较

以10个海南油茶无性系为研究对象,通过显微观察法—石蜡切片观察叶片解剖结构应用变异系数、相关分析和聚类分析对叶片解剖结构进行了解,采用隶属函数对各品种的耐热性进行综合评价,探讨海南油茶叶片解剖结构与植株耐热性的关系,为海南省油茶耐热品种选育、引种栽培提供理论依据.结果表明:(1)海南油茶叶片的气孔均分布在下表皮,气孔特...     

两种微生物液体肥对香花油茶幼苗生长的影响

为了解微生物液体肥对植物生长的作用,利用香花油茶（Camellia osmantha）果壳和柑橘（Citrus reticulata）落果配合微生物EM菌剂分别制备液体肥,设置3个浓度（1∶300、1∶650和1∶1 000）淋施,探究不同微生物液体肥对香花油茶幼苗生长及叶片氮（N）、磷（P）和钾（K）含量的影响。结果表明,两种液体肥处理的幼苗存活率均为96.7%,分别比清水和复合肥水溶液高出30%和10%。液体肥A和液体肥B的苗高、叶芽数和叶片数增量均显著高于复合肥水溶液处理和清水处理;除浓度1∶300的柑橘落果+EM菌液外,其他处理的地径增量均大于复合肥水溶液处理和清水处理。浓度1∶300的柑橘落果+EM菌液有利于N和K积累,浓度1∶1 000的香花油茶果壳+EM菌液有利于P积累。     

12个樱花新品种的耐热性研究

樱花是早春重要的观花植物,在城市园林绿化和美丽乡村建设中具有重要的作用.本研究采用电导率法测定了12个樱花新品种叶片在40℃、45℃、50℃、55℃、60℃、65℃、70℃下细胞伤害率的变化,利用Logistic方程,计算出其高温半致死温度(LT50),结合夏季高温后的热害等级数据,进行聚类分析和耐热性评价.结果表明:...     

油料冷榨及在油茶加工中的应用前景

阐述了油料冷榨的概念、工艺路线及相关特点,综述了油料冷榨技术的发展现状。通过与目前传统压榨、溶剂浸提法的比较,分析了冷榨技术在油茶加工中的优势和应用前景。     

自然降温对不同蜡梅品种1a生枝条抗寒性的影响

自然降温过程中对蜡梅1a生枝条的相对电导率、丙二醛含量和可溶性蛋白质含量进行测定,结果表明不同蜡梅品种之间存在着抗寒性差别,3个供试品种抗寒性的顺序为:‘玉碗藏红'>‘出水芙蓉'>‘琥珀'。     

Effects of radiational heating at low air temperature on water balance, cold tolerance, and visible injury of red spruce foliage

Recent studies have shown that winter needle mortality in red spruce (Picea rubens Sarg.) is increased by exposure to direct solar radiation, possibly as a result of photo-oxidative damage, accelerated winter desiccation, or reduced cold tolerance due to heating of sun-exposed needles. In an experiment at controlled subfreezing air temperatures of -10 to -20 degrees C, visible radiation was less effective than infrared radiation in producing needle desiccation and visible injury during freeze-thaw cycles. However, visible radiation produced a red-brown color in injured needles, similar to natural winter injury, whereas injured needles exposed to infrared radiation were yellow and injured needles kept in darkness were dark brown. Thus, visible radiation was necessary to produce the red-brown color of damaged needles, but not the injury itself. Needle desiccation was not strongly correlated with visible injury, but the pattern of variation in visible injury among trees and the positive correlation between electrolyte leakage and visible injury suggested that freezing damage following freeze-thaw cycles might cause the visible injury. This was confirmed by a second experiment that showed loss of cold hardiness in needles thawed by radiational heating for six consecutive days. Even with a constant nighttime temperature of -10 degrees C, six days of radiational heating of needles to above freezing caused a small (2.8 degrees C) mean decrease in needle cold tolerance, as measured by electrolyte leakage. Continuous darkness at -10 degrees C for six days resulted in an estimated 5.6 degrees C mean increase in needle cold tolerance. Freezing injury stimulated desiccation: cooling at 4 degrees C h(-1) to -43 or -48 degrees C increased the dehydration rate of isolated shoots by a factor of two to three during the first day after thawing. Within three days at 15 to 22 degrees C and 50% relative humidity, the mean water content of these shoots fell to 60% or lower, compared to 90% or greater for unfrozen controls or shoots subject to less severe freezing stress. In some but not all severely freeze-stressed shoots, accelerated needle desiccation and abscission were accompanied by a red-brown color typical of red spruce winter needle injury. We conclude that severe winter desiccation in red spruce may often be due to prior freezing injury, increased as a result of exposure to direct solar radiation. Furthermore, freezing injury in red spruce may sometimes cause desiccation and abscission of green needles.     

冷藏库结构温度应力的计算

作者着重的从理论上分析了冷藏库结构的内力计算方法,并结合实例加以验正。     

高温胁迫下21个山茶种质的生理生化响应

为给山茶属植物的资源评价及进一步开发利用提供科学依据,以21个山茶种质为材料,研究了高温胁迫条件下的相对电导率、叶绿素含量、丙二醛含量和SOD活性变化情况。结果表明,随着温度的升高,21个山茶种质的相对电导率升高,且呈"S"型曲线,XSC14等5个种质的半致死高温均达60℃以上。高温胁迫促使21个山茶种质的叶绿素含量均有不同程度的下降。结合MDA含量和SOD活性测定结果,发现XSC20、XSC14耐热性较强,而XSC4耐热性较差。     

Rapid predictions of cold tolerance in Douglas-fir seedlings using chlorophyll fluorescence after freezing

Chlorophyll fluorescence measurements were performed on the foliage of 3-year-old (11/2+11/2) nursery-grown Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings after exposure to controlled freezing temperatures, in the laboratory, to assess low temperature tolerance. The seedlings were propagated in an Irish nursery and lifted at monthly intervals overwinter 1999 and 1999–2000. Excised shoots from first-order laterals were frozen, in the dark. After freezing, needles were immediately assessed using chlorophyll fluorescence. The excised shoots were then maintained under controlled conditions for 14 days and visually assessed for needle damage. The chlorophyll fluorescence parameter, F _v/F _m, accurately predicted cold hardiness and was linearly related to visual needle damage and short-term survival. An equation was constructed using F _v/F _m data for determining the LT₅₀, that is, the freeze temperature causing 50% seedling damage. The predictions of F.LT₅₀ (fluorescence-based empirical determination of LT₅₀) have been tested over two seasons (i.e., against a second independent data set) with variability between 0 and 1.8°C of visual estimates, though predictions were often 1.1°C of the visual assessment. This approach provided a simple, rapid and accurate prediction of cold tolerance, under climatic conditions where in situ measurements are unreliable. The method can be used to predict if Douglas-fir seedlings have developed sufficient tolerance for lifting to the cold-store, or for planting.     

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.     

两个山茶品种光合荧光参数日变化对春季低温的响应

为了了解山茶在低温下光合作用的机理及其耐寒性,在室外自然低温条件下,测定了抗寒性不同的2个山茶品种("Red Aurora"抗寒性高于"April Pink")光合和荧光参数的日变化,并对其进行比较。结果表明:2个山茶品种叶片的净光合速率日变化均呈双峰曲线,具有明显的"午休"现象。山茶品种Red Aurora光合午休是受非气孔因素的影响,而April Pink光合午休既受气孔限制方面的影响,也受非气孔限制方面的影响;2个山茶品种的净光合速率与气孔导度和蒸腾速率呈极显著正相关,与胞间CO2浓度呈极显著负相关;2个山茶品种在春季低温下均不同程度地发生光抑制,随着白天温度升高和光照时间的延长,Red Aurora光抑制现象得到一定程度的恢复,而April Pink基本没有恢复。2个品种PSⅡ电子传递量子效率,光化学淬灭系数都表现出"升高-降低-升高"波动的变化趋势,Red Aurora的变化幅度大于April Pink。与抗寒性弱的April Pink相比,Red Aurora具有较强的光能利用能力和避免强光低温伤害的能力。