The objective of this study was to determine how xanthophyll cycle-dependent thermal dissipation and the antioxidant system in the peel of apple fruit respond to the natural light exposure within the tree canopy. Fruit from exterior and interior canopies of both mature 'Gala' and 'Smoothee' apple trees were sampled at noon and/or predawn to measure chlorophyll fluorescence, xanthophyll cycle pool size and composition, and enzymatic and non-enzymatic antioxidants. Compared with the shaded side, the sun-exposed peel of the fruit had more excess absorbed photon flux density (PFD) as a result of a lower photosystem II operating efficiency and a higher incident PFD at noon. The efficiency of excitation transfer was lower in the sun-exposed peel than in the shaded peel, indicative of higher thermal dissipation. The sun-exposed peel had a larger xanthophyll cycle pool size and a higher conversion state. It also had higher activities of ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase, and a larger size and a higher reduction state of the ascorbate pool and the glutathione pool. However, catalase activity was lower in the sun-exposed peel than in the shaded peel. Superoxide dismutase did not show significant trend with regard to fruit peel type or position in the canopy. We conclude that both the xanthophyll cycle and the ascorbate/glutathione pathway in the apple fruit peel are acclimated to the prevailing light exposure within the tree canopy to meet the respective needs for dissipating excess absorbed PFD and detoxifying reactive oxygen species.

介绍了一种从木本植物组织中获得高质量RNA 的快速、简单和高效的核酸提取方法。该方法是基于核酸的二氧化硅捕获，避免了使用苯酚、氯仿等有机溶剂。利用该方法从樱桃组织中提取的总RNA 用RT 2PCR技术检测PDV，PNRSV 均获得成功。从感病植株的一年生枝的叶片、韧皮部及芽组织中扩增出了预期的目的片段，即172和449bp，而健康组织中无此扩增带。该法提取的总RNA用于RT 2PCR技术检测，其敏感性至少与商业出售的Qiagen RNeasy提取试剂盒相当，但简单经济。

研究了影响山杏下胚轴再生的有关因素，首次获得了山杏下胚轴再生植株。结果表明：在附加TDZ2mg/L、AA0.5mg/L的改良MS培养基（1/2 NH4NO3）上愈伤组织诱导率（100%）和再生频率（37.5%）均最高，TDZ效果优于6-BA，不定梢在改良MS+IBA0.2mg/L培养基上生根率为75.8%。

Bench-grafted 'Fuji/M.26' apple (Malus domestica Borkh.) trees received a constant nitrogen (N) supply (10.7mM) from bud break to the end of June, and were then fertigated with 0, 5, 10, 15 or 20mM N in a modified Hoagland's solution for 2 months during the summer. In mid-October, half of the trees fertigated at each N concentration were sprayed twice with 3% urea, whereas the remaining trees served as controls. All trees were harvested after natural leaf fall and were stored at 2℃. Five trees from each of the N treatment combinations were destructively sampled during dormancy to determine the composition of N and total nonstructural carbohydrates (TNC). As the N supply from fertigation increased, amounts of N in both free amino acids and proteins increased, whereas C/N ratios decreased. Foliar urea applications in the fall significantly increased amounts of N in both free amino acids and proteins, but decreased their C/N ratios. Arginine, the most abundant amino acid in both free amino acids and in proteins, accounted for an increasing proportion of N in free amino acids and proteins with increasingNsupply from fertigation or foliar urea application. The ratio of proteinNto free amino acidNdecreased from about 27.1 to 3.2 as N supply from fertigation increased from 0 to 20mM, and decreased further to 3.0 in response to foliar urea applications in the fall. Concentrations of glucose, fructose, sucrose and TNC decreased as theNsupply from fertigation increased, whereas concentrations of sorbitol and starch remained relatively unchanged. Foliar urea applications decreased the concentration of eachTNCcomponent and theTNCconcentration in each N fertigation treatment. A negative linear relationship was found between carbon in TNC and N in proteins and free amino acids. The sum of carbon in TNC, proteins and free amino acids remained constant in response to N supply from fertigation. However, foliar urea applications decreased the sum of carbon in proteins, free amino acids and TNC because about 21% of the decrease in TNC carbonwas not recovered in free amino acids or proteins.Young apple trees storeNand carbon dynamically in response to N supply. As N supply increases, an increasing proportion of N is found in the form of free amino acids, which have a low carbon cost, although proteins remain the main form of N storage. Furthermore, part of the carbon from TNC is incorporated into amino acids and proteins, proteins, decreasing the carbon stored as TNC and increasing the carbon stored as amino acids and proteins.

蔷薇科植物中，与山梨醇代谢相关的酶主要有：62磷酸山梨醇脱氢酶、山梨醇脱氢酶和山梨醇氧化酶。综述了近些年来国内外关于这几种酶的研究进展，涉及的内容有：酶的性质与作用、酶的活性变化与转录的关系，及其在生物技术方面的研究成果，并对今后的研究工作进行了展望。

在45℃下对猕猴桃一年生盆栽苗进行2，4，6，8，10h的高温胁迫，测定高温胁迫下叶绿素含量、相对膜透性、丙二醛（MDA）含量、抗氧化酶活性和抗氧化剂含量及热激蛋白等生理生化指标。结果表明，高温胁迫下叶绿素含量下降，相对膜透性增大，MDA 含量增加； 超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、抗坏血酸还原酶（APX）活性均在胁迫初期呈上升趋势，随处理时间延长，活性下降；随胁迫时间延长，还原型谷胱甘肽（GSH） 含量先升后降，抗坏血酸（ASA）含量总体呈下降趋势，谷胱甘肽还原酶（GR）和脯氨酸含量一直呈上升趋势；热激蛋白（HSP）在高温下被诱导。

Approximately 80 days after full bloom, well-exposed fruit on the south part of the canopy of mature Liberty/M9 apple (Malus domestica Borkh.) trees were randomly assigned to one of the following two treatments. Some fruits were turned about 180◦ to expose the original shaded side to full sun, whereas the rest served as untreated controls. On days 0, 1, 2, 4, 7 and 10 after treatment, fruit peel samples were taken from the original shaded side of the treated fruit and both the sun-exposed side and the shaded side of the control fruit at midday, to determine photosynthetic pigments, enzymatic and non-enzymatic antioxidants. Maximum photosystem II (PSII) efficiency, measured as Fv/Fm (maximum fluorescence) of chlorophyll fluorescence at pre-dawn, was higher in the shaded side than the sun-exposed side of the control fruit. Fv/Fm of the original shaded side decreased sharply after 1 day exposure to full sun, and then gradually recovered to a similar value of the sun-exposed side of the control fruit by day 10. The shaded side of the control fruit had much lower xanthophyll cycle pool size, conversion and antioxidant enzymes and also soluble antioxidants of the ascorbate–glutathione cycle than the sun-exposed side. Xanthophyll cycle pool size of the original shaded side increased in response to full sun exposure, reaching a similar value of the sun-exposed side by day 10. Almost all the xanthophyll cycle pool was converted to zeaxanthin and antheraxanthin starting from the first day of exposure to full sun. In contrast, chlorophyll content decreased whereas lutein or neoxanthin content remained unchanged. In response to full sun exposure, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase and total pool size and reduction state of both ascorbate and glutathione, all increased to the corresponding values found in the sun-exposed side of the control fruit over a 10-day period. It is concluded that both xanthophyll cycle and the ascorbate-glutathione cycle in the original shaded side are up-regulated in response to full sun exposure to minimize photo-oxidative damage and contributes to its acclimation to full sun.

Libertyʼ) were monitored in the fi eld over a diurnal course at about 3 months after full bloom. Compared with leaves, sun-exposed peel of apple fruit had much lower photosystem II operating effi ciency at any given photon fl ux density (PFD) and a larger xanthophyll cycle pool size on a chlorophyll basis. Zeaxanthin (Z) level increased with rising PFD in the morning, reached the highest level during midday, and then decreased with falling PFD for the rest of the day. At noon, Z accounted for >90% of the xanthophyll cycle pool in the fruit peel compared with only 53% in leaves. Effi ciency of excitation transfer to PSII reaction centers (Fv'/Fm') was negatively related to the level of Z in fruit peel and leaves throughout the day. In fruit peel, the antioxidant enzymes in the ascorbate-glutathione cycle, ascorbate peroxidase (APX), monodehydroascorbate reductase (MDAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) showed a diurnal pattern similar to that of incident PFD. In contrast, the activities of APX and GR in leaves did not change signifi cantly during the day although activities of both MDAR and DHAR were higher in the afternoon than in the morning. In both fruit peel and leaves, superoxide dismutase activity did not change signifi cantly during the day; catalase activity showed a diurnal pattern opposite to that of PFD with much lower activity in fruit peel than in leaves. The total ascorbate pool was much smaller in fruit peel than in leaves on an area basis, but the ratio of reduced ascorbate to oxidized ascorbate reached a maximum in the early afternoon in both fruit peel and leaves. The total glutathione pool, reduced glutathione and the ratio of reduced glutathione to oxidized glutathione in both fruit peel and leaves also peaked in the early afternoon. We conclude that the antioxidant system as well as the xanthophyll cycle responds to changing PFD over the course of a day to protect fruit peel from photooxidative damage.

以雌蕊败育率不同的2个杏品种Tyinthos（败育率低）和金杏（败育率高）为试材，于花芽分化后期（9月中旬）各选一枝条进行14G标记，研究其14G同化物的分配规律。结果表明，Tyinthos花芽在各个时期的同化物比强、花芽的同化物分配率、叶片的光合产物利用率均高于金杏。

用0.5mmol/L抗坏血酸（ASA）处理苹果组培苗，在42℃的条件下进行高温胁迫处理不同时间，研究了细胞膜相对透性、丙二醛（MDA）含量、抗氧化酶活性以及抗氧化剂含量的变化。结果表明，高温胁迫下，膜透性、MDA含量持续增加；抗氧化酶SOD、CAT、POD活性先降后升，APX活性一直呈下降趋势；抗氧化剂ASA含量持续下降，GSH含量不断增加。ASA处理可以有效地抑制抗氧化酶活性的下降，提高酶活性；同时还抑制ASA含量的下降，从而延缓膜透性和丙二醛含量的增加；但同时也抑制了GSH含量的增加。结果说明，高温对苹果造成了伤害，苹果体内也启动了相应的适应性生理生化机制；ASA处理可以诱导苹果的耐热性。