低温胁迫对不同杏品种抗性指标的影响

以常见的串枝红、沙金红、兰州大接杏3个杏品种为试验材料,在自然低温和人工低温下对其枝条中的丙二醛(MDA)、游离脯氨酸、可溶性蛋白3个生化指标进行测定分析,结果表明:随温度下降,MDA含量呈上升趋势,抗寒性差的品种MDA含量高于抗寒性强的品种;游离脯氨酸含量和可溶性蛋白含量均有明显增加,且抗寒性强的品种增加幅度大于抗寒性差的品种;3个品种抗寒性排序为:串枝红沙金红兰州大接杏。     

枣树稀有大果型鲜食品种

枣树稀有大果型鲜食品种大瓜枣和大白铃枣是山东果树所精选的两个稀有大果型鲜食枣树品种，并且早实、丰产、质优，当年抽生的发育枝分枝形成的结果枝即有很强的结果能力。（１）大瓜枣。果实近球形或短椭圆形，纵径３６ｃｍ，横径３．８５ｃｍ。１年生枝系的单果平均重１...     

高接换头在枣树上的应用

冬枣是我国的名优品种之一,皮薄酥脆,含糖量高,风味独特,市场前景看好,不少老枣园想改接冬枣,以提高经济效益．2001年兴安镇贾村50亩15年-20年生的婆枣和铃枣进行多头高接冬枣,嫁接成活率为96％,当年新枣头的生长量为100-130厘米,取得了一年嫁接,二年结果,三年亩产35公斤的好收成。技术要点如下：     

鲜食枣良种——苹果枣栽培技术要点

苹果枣又名脱毒冬枣（Zizyphus jujuba Mill．）为鼠李科（Rhamnaceae）枣属，起源于河北黄骅、衡水一带，属冬枣的自然芽变品种，经过多年的试验研究，筛选出来的一个名贵稀有的优良鲜食品系。     

枣不同品种花发育时间节律比较

【目的】为深入研究枣树快速成花机制和花期调控等提供参考依据。【方法】以极早熟品种‘月光’、中熟品种‘京枣39’和极晚熟品种‘冬枣’为试材,从结果母枝(枣股)主芽萌动起,连续采集新生枣吊(结果枝),利用石蜡切片法进行花芽形态分化的观察;自零级花蕾出现至零级花开放结束连续采样,使用XTJ-4400体视显微镜观察花蕾形态发育和单花开放过程,使用CAM-MA成像软件进行拍照。【结果】不同品种花发育过程各阶段的形态学特征高度一致,但各发育阶段的历时在品种间存在显著差异。3个品种花芽分化均呈"快—慢—快"的规律,即萼片期向花瓣期分化历时最长,其前后各分化阶段的历时相对较短。在多年生枝上,‘月光’‘京枣39’‘冬枣’的单花完成花芽分化分别约需8、11和13 d,花蕾发育分别约需26、28和34 d,单花开放全过程历时均为1～2 d。‘月光’‘京枣39’‘冬枣’从花芽开始分化到单花开放完成分别约需36、41和49 d。与多年生枝条相比,‘冬枣’当年生新枝上花的发育进程明显较慢,单花完成花芽分化、花发育和单花开放分别约需21、37和2 d,共历时约60 d。【结论】不同品种花发育进程存在显著差异;品种间花发育进程的差异主要表现在花芽分化的萼片期和花瓣期及花蕾发育阶段,单花开放的速度基本一致;当年生枝上花的发育速度明显慢于多年生枝。     

南方枣品种花粉育性与花药内源激素的变化

对南方茶陵长枣、金丝小枣、糖枣、鸡蛋枣和冬枣的花粉发芽率进行了试验,并利用酶联免疫检测(ELISA)技术,研究其花药在黄蕾期、初开期、萼平期、瓣离期和瓣平期花药内源吲哚乙酸(IAA)、赤霉素(GA3)、玉米素核苷(ZR)和脱落酸(ABA)含量的动态变化。结果表明,南方各枣品种花粉育性与其花药发育期内源激素变化具有相关性;茶陵长枣、金丝小枣、糖枣花粉育性高,鸡蛋枣次之,冬枣最差;育性高的3个品种花药间内源激素含量差异不明显,但与鸡蛋枣差异显著、与冬枣花药间差异极显著;在IAA、GA3和ZR含量上,冬枣花药低于鸡蛋枣,远低于茶陵长枣、金丝小枣和糖枣;但在ABA含量上,冬枣花药高于其它4个品种花药,这种差异在萼平期达最大值。     

5个枣品种叶片过氧化物酶与酯酶同工酶的研究

采用聚丙烯酰胺凝胶电泳法,对江苏省目前主栽的5个枣品种叶片的过氧化物酶与酯酶同工酶的酶谱进行分析,并通过聚类分析法对其亲缘关系进行研究.结果表明：（1）9月测定枣树叶片的过氧化物酶与酯酶,其谱型稳定,重复性好;（2）5个供试枣品种的过氧化物酶共显现3种谱型,5条酶带,酯酶共显现4种谱型,14条酶带;（3）聚类分析结果表明,冬枣是较其他4个枣品种亲缘关系最远的品种,泗洪沙枣与蜂蜜罐的亲缘关系最近,蚂蚁枣与泗洪大枣介于冬枣与蜂蜜罐之间, 泗洪大枣与泗洪沙枣的亲缘关系较远,是2个不同的枣品种.     

冬枣嫁接苗枝条抗寒力的对比

为给冬枣的栽培、引种及有效利用提供依据,以沧县栽植的5个不同原产地的冬枣嫁接苗休眠期1年生枝为材料,用电导法分别测定其在自然条件和不同低温处理下细胞膜透性的变化,同时结合恢复性生长试验,测定其在不同低温处理后枝条的发芽率,分析研究了不同产地和不同粗度冬枣枝条的抗寒力。结果表明,在沧县地区栽植的不同原产地的冬枣在自然种植条件下无冻害发生,其中沧县和乐陵产地苗木在同等条件下抗寒力较好;枝条相对电导率随枝条粗度的增加而升高;自然状态下,不同原产地冬枣的1年生枝随着外界气温的降低相对电导率升高;降温处理后,不同原产地冬枣枝条的相对电导率随处理温度的降低而升高,发芽率随处理温度的降低而降低。     

冬枣的形态特征及其与其他晚熟枣品种的区别

为澄清对冬枣的模糊认识,对冬枣及其他晚熟枣品种在多种性状上进行了比较,认为冬枣不应包含任何其他晚熟枣品种,其定义应严格以《中国果树志·枣卷》为准。建议进行冬枣遗传变异研究,并对枣树品种命名进行科学规范。     

冬枣丰产栽培技术

冬枣作为第2代鲜食枣品种,以汁多、味甜、质脆、无渣等特点深受消费者欢迎,是我国目前综合性状最好的鲜食品种,在我国北方枣区面积迅速扩大,得到了快速发展。但是,许多枣农还沿用传统的梨枣管理模式,对冬枣进行管理,这就推迟了冬枣的丰产期,造成了不必要的损失。为了使冬枣得到科学栽培,发挥其最好的经济效益,现将该品种的栽培技术要点介绍如下:1　冬枣的生物学特性冬枣属晚熟鲜食品种,与其他品种相比,树势中庸偏弱,树枝开张,发枝力中等,枝叶较密,易造成树冠内堂郁闭,通风透光不良。以3～8年枣股结果最好,每个枣股上抽生3～10个枣吊,枣…     

日照地区部分竹子的抗寒性研究

冬季低温是竹类植物在我国较高纬度地区园林绿化中得不到进一步推广应用的主要限制因子,为探究其抗寒性机理,扩大引种范围,本文以6个竹种（品种）为试材,测定电解质外渗率并拟合logistic方程求LT50,研究低温对可溶性糖、可溶性蛋白、游离脯氨酸等生理生化指标的影响。结果表明,随着低温胁迫加剧,电解质外渗率呈增加趋势,可溶性糖含量、可溶性蛋白含量、游离脯氨酸含量均表现出先上升后下降的趋势。综合所有抗寒性指标分析得出,6个竹种（品种）抗寒性顺序为：金镶玉竹〉矢竹〉罗汉竹〉苦竹〉箬竹〉鸡毛竹。     

Comparison of three cold hardiness tests for conifer seedlings

Greenhouse-cultured, container-grown ponderosa pine (Pinus ponderosa var. scopulorum Engelm.), interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), and Engelmann spruce (Picea engelmannii (Parry) Engelm.) were cold acclimated and deacclimated in growth chambers over 19 weeks. Cold hardiness was measured weekly by a whole-plant freeze test and by two quick tissue tests: freeze-induced electrolyte leakage of needles, and differential thermal analysis of buds. The whole-plant freeze test provided results in 7 days, and indicated differences in cold hardiness among stems, buds, and needles. Although the whole-plant freeze test could accurately measure cold hardiness, it was not precise, and it required destructive sampling. Results from freeze-induced electrolyte leakage and differential thermal analysis were available in 2 days and 1 hour, respectively. The freeze-induced electrolyte leakage test was a precise, sensitive and objective predictor of changes or differences in tissue cold hardiness. To determine actual cold hardiness, results could be calibrated to the response of the same tissue in the whole-plant freeze test. The speed and objectivity of differential thermal analysis made this test useful for rapid, general assessment of cold hardiness status, but calibration was difficult, and precision varied.     

Morphological and physiological differences in Scots pine seedlings of six seed origins

One-year-old seedlings of Scots pine (Pinus sylvestris L.) offour native seed origins (Loch Maree Islands, Glengarry/GlenMorriston, Glen Affric and Abernethy), a commercial Britishseedlot, and a seedlot from Hedesunda, in middle Sweden, werecompared at monthly intervals from October 1993 to April 1994.Seedling morphology, root condition, root frost hardiness andbud dry matter were determined at each date. There were clear morphological differences among seed origins.Seedlings raised from the commercial seedlot (A70) were largerbut had a poorer root:shoot ratio than the other seed origins.Of the native pines tested, the Loch Maree Islands origin allocateda larger proportion of its photosynthate to fine roots and needlesand smaller proportion to woody structures. Seedlings raised from the commercial British seedlot tendedto have poorer bud lignification than the other origins andalso, in autumn, higher electrolyte leakage rates from its fineroots. During winter, the Swedish origin had the lowest fineroot electrolyte leakage. Seedlings of all origins showed aprogressive increase in fine root hardiness towards mid-winterwith maximum hardiness (–7°C) in January. Dehardeningoccurred over subsequent months reaching –3°C in April.Differences among origins were evident. The Swedish seedlotdeveloped greater frost resistance than the other origins, hardeningbegan earlier in autumn and dehardening began later in spring.The commercial seedlot hardened later than the other originsbut reached a similar level of frost hardiness by January. Ofthe native pines, seedlings of the Loch Maree Islands originwere slowest to develop root hardiness.     

Variation in cold hardiness and carbohydrate concentration from dormancy induction to bud burst among provenances of three European oak species

Although cold hardiness is known to be a major determinant of tree species distribution, its dynamics and the factors that regulate it remain poorly understood. Variation in cold hardiness and carbohydrate concentration, from dormancy induction until bud burst, were investigated in populations of two deciduous (Quercus robur L. and Quercus pubescens Willd.) and one evergreen (Quercus ilex L.) European oak. Mean cold hardiness values in January were -56, -45 and -27 degrees C for Q. robur, Q. pubescens and Q. ilex, respectively. Soluble carbohydrate concentrations were closely related to instantaneous cold hardiness, estimated by the electrolyte leakage method, whereas total carbohydrate concentration was related to maximum cold hardiness. Both cold hardiness and carbohydrate concentration showed a close linear relationship with temperatures at the location of the sampled population. Our results show that temporal variation in both the inter- and intraspecific cold hardiness in European oaks can be related to variations in the concentrations of soluble carbohydrates and that these relationships appear to be driven by temperature.     

Assessment of seedling storability of Quercus robur and Pinus sylvestris

Pedunculate oak (Quercus robur L.) and Scots pine (Pinus sylvestris L.) seedlings were lifted on several occasions during autumn 1997 to determine the relationships between storability and frost hardiness. On each lifting date their physiological status was determined by assessment of shoot and root electrolyte leakage and frost hardiness, assessed as freeze-induced electrolyte leakage. Additional seedlings were simultaneously cold-stored for field planting and assessment of preplanting root growth potential in April 1998. First year field performance was determined the following winter. Storability and cold acclimation patterns differed between the two species. Both were negatively affected by early lifting, but oak was less sensitive with respect to survival, and pine attained tolerance to cold storage more rapidly and earlier with respect to growth increment. The correlations between shoot frost hardiness and performance suggest that freeze-induced shoot electrolyte leakage (SEL_diff?20) below a threshold of 5% is a good storability predictor for Scots pine in Denmark. A completely reliable criterion for pedunculate oak could not be established.     

A semi-physiological model of cold hardening and dehardening in walnut stem

It has been hypothesized that the increase in temperature in this century could lead to an increase in frost damage to plant tissues. Several models have been proposed to describe the development of cold hardiness, but never taking into account extreme climatic and/or physiological events. Our results on walnut tree (Juglans regia L.) show that cold hardiness was best correlated with average daily temperatures minimal temperatures over the last 15 days before sampling (T(min 15 days)), indicating that the freezing tolerance depended on the tree's climatic history. Moreover, this study also shows that the accumulation of sucrose and the water content (WC) decrease are an essential step towards cold hardiness. Thus, a simple linear model based on climatic (T(min 15 days)) and physiological (soluble sugars, WC) explanatory variables was developed to predict the cold hardiness level in walnut stem at any time during the leafless period. Each of the three input variables can be assigned a specific role contributing to the simulated function, cold hardiness. The extent and robustness of this relation was assessed on extreme physiological events on walnut trees bearing three main branches. On each tree, one branch was defoliated to limit the local carbohydrate and transpiration, one was girdled to increase local carbohydrate and prevent carbohydrate export and the third one was kept untreated as control. As expected, these treatments impacted both local carbon reserves and WC in the stems born by each main branch in comparison with the control on the same tree. The impact of these treatments on stem's freezing tolerance, as evaluated by an electrolyte leakage method (LT??), confirmed the direct impact of soluble sugar and WC on cold hardiness over a wide range of carbohydrate and WC. This is discussed in relation to the branch autonomy theory for carbon but also for water during summer growth and winter periods. The present study demonstrates the importance of physiological parameters in the prediction of cold hardiness and proposes a way to model cold hardiness with extreme climatic and/or physiological events.     

Frost hardiness gradients in shoots and roots of picea mariana seedlings

Frost hardiness of tissues along the length of the stem and the root was investigated in first‐year black spruce (Picea mariana (Mill.) B.S.P.) seedlings. Frost hardiness of 1 cm long stem and root segments was evaluated based on Index of Injury, calculated from post‐freezing electrolyte leakage. Frost hardiness was tested approximately weekly beginning seven weeks after seedlings were transferred from an 18 to a 10 h photoperiod, both at day/night temperatures of 26°C/16°C. Trees were transferred to temperatures of 10°C day and 5°C night at a 10 h photoperiod after a further 18 days. Frost hardiness was greater at the terminal bud and least at the root tips. Although shoots were generally more frost hardy than roots, differences in hardiness along the stem and root axes were gradual, rather than abruptly differing at the shoot‐root interface. All tissues, including root tips, increased in frost hardiness after conditioning for 18 days under short photoperiods (10 h) and warm temperatures (26?C/16°C, day/night). Under cold temperatures (10°C/5°C, day/night) all tissues, excepting the root tips, tolerated — 16°C with little subsequent electrolyte leakage.     

Chemical and physiological responses of four Turkish red pine (Pinus brutia Ten.) provenances to cold temperature treatments

Determining the adaptability to abiotic conditions and potential establishment success of tree species needs to be conducted before attempting to use a species in large-scale afforestation programs. In this study, the chemical and physiological performance of four Turkish red pine (Pinus brutia Ten.) provenances was investigated after exposure to artificial cold temperature treatments to determine their adaptability to cold environment for potential use in afforestation programs. Seeds were sown and raised for 24, 28, and 32 weeks and exposed to decreasing temperatures in an artificial freezer. Relative electrolyte leakage, chlorophyll fluorescence, and carbohydrate concentrations were measured to determine the variability between provenances. Results showed that diameter and height growth did not vary with origin for each of the three growth stages measured. Root electrolyte leakage values differed between provenances, confirming that cold stress was effectively causing physiological damages when plants were exposed to temperature at ?15 °C and below. The variability observed in the relationship between provenances and cold hardiness responses can be attributed to tree-to-tree variability within provenances and microsites conditions. There was generally no significant difference in chlorophyll fluorescence between provenances, also attributed to low genetic variation between provenances. Carbohydrate concentrations were also very variable and varied significantly among growth stages and provenances. High-altitude provenances had higher soluble carbohydrates concentrations in several cases, suggesting a relationship between altitude, soluble sugars, and cold hardiness. However, these trends were not consistent; therefore, we suggest that such hypotheses be confirmed through more comprehensive further studies.     

Fall acclimation patterns of interior spruce seedlings and their relationship to changes in vegetative storage proteins

Changes in the content of vegetative storage proteins (VSPs) were monitored in 1-year-old interior spruce (Picea glauca (Moench) Voss x Picea engelmanni Parry complex) seedlings from late summer until midwinter. Seedlings were also monitored for days to terminal bud break (DBB(t)), dry weight fraction and frost hardiness, measured as both index of injury at -18 degrees C (IL(-18 degrees C)) and as the temperature causing 50% foliage electrolyte leakage (LT(50)). During fall acclimation, VSP content, frost hardiness and dry weight fraction increased, whereas DBB(t) decreased. In mid-November, IL(-18 degrees C) reached its lowest value, coinciding with high VSP content and dry weight fraction, and low DBB(t). The LT(50) decreased in a linear manner as dry weight fraction and VSP content increased; r(2) values were 0.69 to 0.81, respectively. The fall accumulation of VSPs was also highly correlated with increased dry weight fraction. The increase in VSP content occurred as seedling photosynthetic capacity declined, but maximum contents were obtained before complete inactivation of the photosynthetic apparatus. The results indicate that VSP accumulation is an integral part of fall acclimation in interior spruce, closely parallels frost hardiness and partially accounts for the increase in dry weight fraction.     

几种桉树、木麻黄苗期耐寒性研究初报

以5种桉树和5种木麻黄叶片为材料,在不同低温处理以后,测定其电导率,结果表明:直接采用电导率难以对桉树和木麻黄的耐寒性作出评价,而采用电解质透出率评价耐寒性结果较稳定,对电解质透出率配以Logistic曲线方程,且以处于拐点附近的温度做为半致死温度,能定量地评价其耐寒性,为早期选择耐寒桉树和木麻黄提供科学依据。