Ascorbate levels and the activity of key enzymes in ascorbate biosynthesis and recycling in the leaves of 22 Chinese persimmon cultivars

The objective of this study was to determine diversities of ascorbic acid (AsA) and activities of enzymes involved in AsA metabolism, and to determine their relationships to AsA content in the leaves of Chinese persimmon (Diospyros kaki) cultivars. Results showed that there were huge differences not only in the contents of AsA and glutathione (GSH) but also in the enzyme activities of l-galactono-1,4-lactone dehydrogenase (GLDH, EC 1.3.2.3), dehydroascorbate reductase (DHAR, EC 1.8.5.1), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) in the leaves of 22 Chinese persimmon cultivars. Control of AsA levels mainly depended on the capacity for biosynthesis and GLDH activity played a main role in determining AsA levels in the leaves of persimmon. Both MDHAR and DHAR, MDHAR in particular, also played an important role in maintaining AsA redox state by reducing oxidized AsA back to AsA. But contents of GSH and hydrogen peroide (H₂O₂) and activity of APX were not significantly correlated with AsA content in the leaves of persimmon.     

老鸦柿的开发利用

经过５年的试验实践，将野生灌木老鸦柿按其浆果形态的差异区分成３个类型。并对其栽培利用作了较为系统的归纳，将为今后的开发利用提供参考。     

6-苄基腺嘌呤对甜柿次郎果实中糖、酸含量的影响

以甜柿次郎为试材,100￣200 mg/L的6-BA于花后10天喷果,结果表明:均提高了果实还原糖、可溶性糖、TSS含量及固酸比;促进果实淀粉降解;对可滴定酸含量影响不大。     

柿果实脱涩机理及脱涩技术研究进展

随着人们对柿果实保健功能的深入认识,柿树栽培面积和产量逐年上升。但中国在柿采后生理尤其是涩柿脱涩机理及相应技术的研究仍滞后于产业发展的需要,是制约目前柿产业发展的关键问题之一。本文综述了柿不同类型果实脱涩机理及涩柿采后脱涩技术及相关影响因子,旨在为相关研究和产业发展提供参考。     

不同因素对磨盘柿色素稳定性的影响

通过对磨盘柿果实色素的乙醇提取液进行不同处理 ,对果实色素的稳定性进行了研究。在阳光直射 5d以内、室内自然光照射 2 5d以内或在室内避光保存 30d以内的条件下 ,磨盘柿色素在可见光区的最大吸收波长未发生改变 ,但吸光值降低 ,柿色素保留率在 6 0 %以上 ;80℃以上的高温对柿色素有破坏作用 ,但 6 0℃ ,2h以内的高温条件下柿色素的稳定性良好 ;柿色素溶液在pH 6～ 11范围内呈稳定状态 ;供试的 9种金属离子中 ,铁离子对柿色素的稳定性影响最大 ,0 12 5mmol·L-1以上的铁离子使柿色素溶液变浑浊 ,出现沉淀 ,Cu2 + ,Ca2 + 和K+ 次之 ,而Al3 + ,Na+ ,Zn2 + 和Mg2 + 影响较小。质量分数为 1%的苯甲酸钠和山梨酸钾对柿色素稳定性影响不大 ;而质量分数为 2 %的VC对柿色素有保护作用。在加工利用和保存柿色素时 ,需提供有利柿色素的稳定条件 ,才能保持柿色素的营养价值。     

Persimmon breeding in Japan for pollination-constant non-astringent (PCNA) type with marker-assisted selection

Oriental persimmon (Diospyros kaki) originated in Eastern Asia, and many indigenous cultivars have been developed in China, Japan, and Korea. These cultivars are classified into four groups based on their natural astringency loss on the tree and seed formation: pollination-constant non-astringent (PCNA), pollination-variant non-astringent (PVNA), pollination-constant astringent (PCA), and pollination-variant astringent (PVA). PCNA is the most desirable type because the fruit can be eaten without any postharvest treatment; therefore, one of the goals of our persimmon breeding programs is to release superior PCNA cultivars. The PCNA genotype is recessive to the other three non-PCNA genotypes, and PCNA-type F₁ offspring are obtained exclusively from crosses among PCNA genotypes. Moreover, the number of superior PCNA cross-parents have been limited. In the late 1980s, inbreeding depression became obvious, especially in terms of fruit size, tree vigor, and productivity. To mitigate the inbreeding, a backcross program using PCNA [(non-PCNA × PCNA) × PCNA] was started in 1990. This process, however, was inefficient because only 15% of the offspring were PCNA, and all offspring had to be grown to the fruiting stage. Therefore, molecular markers linked to the PCNA locus were developed for discriminating PCNA offspring. A molecular marker linked to Chinese PCNA has also been developed.     

‘禅寺丸’大小孢子发生与雌雄配子体发育

为探究禅寺丸大小孢子发生及雌雄配子体发育过程,并观察是否存在花粉及胚囊败育现象,采用常规石蜡切片法对其大、小孢子发生和雌、雄配子体发育的过程进行观察。结果表明:禅寺丸花药四室,花药壁由表皮、药室内壁、中层和腺质绒毡层组成;小孢子母细胞减数分裂为同时型,四分体的排列方式为四面体型;成熟花粉粒为2-细胞型,有3个萌发孔;不同药室间及同一药室内的小孢子母细胞减数分裂不同步,且有巨大花粉(未减数花粉)的产生。子房8室,中轴胎座,胚珠倒生,双珠被,薄珠心和单孢原细胞;大孢子四分体直线排列,功能大孢子位于合点端,蓼型胚囊。禅寺丸花粉和胚囊发育过程多数正常,不仅可作为授粉树种,也可作为优良的杂交母本。     

土壤水分对柿树光合光响应特性的影响

采用CIRAS-2便携式光合仪测定不同土壤水分条件下2年生柿树叶片净光合速率、蒸腾速率、水分利用效率、气孔导度等光合生理参数的光响应过程,探讨柿树光合光响应特性对土壤水分的响应规律。结果表明：土壤水分对柿树的光合生理参数影响显著,随着土壤水分的降低,净光合速率、表观量子效率先升后降,光补偿点先降后升,光饱和点呈下降趋势;维持柿树高光合作用和高水分利用效率的适宜土壤相对含水量为48.8%～76.7%,适宜的光照强度为800～2 000μmol/（m2·s）;柿树对强光利用能力较强,而对弱光的利用效率较低;在土壤相对含水量为48.8%时,柿树光合作用主要受气孔限制,而土壤相对含水量降低到25.5%时,柿树光合作用转变为非气孔限制,通过对气孔、非气孔因素的判定,可知柿树是一种抗旱性非常强的植物。研究结果可为柿树的节水高产栽培提供理论依据。     

基于叶绿体DNA PCR-RFLP分析柿及其近缘种亲缘关系

 应用5对叶绿体DNA（cpDNA）特异引物对柿及其近缘的8个种共32个基因型的cpDNA进行PCR扩增。采用7种限制性内切酶对其扩增产物酶切位点变异分析表明,在供试柿属植物中存在丰富的种间多态性,但供试22个柿种内基因型未检测到变异位点。应用NTSYS中UPGMA法聚类和主坐标分析表明：柿与金枣柿最近缘,其次分别是油柿、云南野毛柿、浙江柿和君迁子,而与美洲柿和乌柿相距较远。野柿（浙江）为柿的变种,聚类结果也表明野柿（浙江）与柿有一定差异。     

浙江省柿树种质资源表型多样性研究

对浙江省8个不同产地的柿树(Diospyros kaki)品种/类型表型性状的变异规律进行研究,结果表明,柿树表型多样性极其丰富,叶片长、叶片宽、叶柄长、叶长宽比、果实长、果实宽、果长宽比、果柄长、果体积、果质量、果密度、果固形物、果可溶性总糖、果蛋白质14个表型性状中除叶长宽比和果长宽比外的12个在品种/类型间和品种/类型内都存在极显著差异(a=0.01);品种/类型间和品种/类型内优株间均存在丰富的变异,且品种/类型间的变异远远大于品种/类型内优株间的变异;利用品种间欧氏距离进行UPGMA聚类分析,所有单株基本按品种/类型聚在一起。