Nutrient Deficiency Affects Root Architecture of Young Seedlings of Malus hupehensis (Pamp) Rehd. Under Conditions of Artificial Medium Cultivation

What the researchers go in for is to establish models between root architecture （RA） changes and nutrition, mold ideal root architecture of apple trees, improve the nutrient uptake efficiency, and further explore the functional mechanism of nutrient elements during the course of RA construction. The cultivation system of filter paper is utilized to research the effect of nutrient deficiency on the RA of Malus hupehensis （Pamp.） Rehd. There may be eight types of RA. In complete Hogland solution, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂. With the lack of P, K or Ca, the main type of RA is ＂lateral roots clustering in the upper region primary root＂, and the ＂lateral roots clustering in the upper and middle regions of primary root＂ types of RA decrease. But with shortage of P, the type of lateral roots clustering in the upper and lower regions of primary root increases, and the type of lateral roots clustering in the middle region of primary root decreases, with the types of RA diversified. Under the condition of K deficiency, the type of no lateral root increases and types of lateral roots clustering in the middle region of primary root decrease, and the percentage of such types as ＂no lateral root＂, ＂lateral roots clustering in the upper region of primary root＂, and ＂lateral roots clustering in the upper and middle regions of primary root＂ accounts for 97.9% in all, with the types of RA simplified. With lack of Fe, Mg or Zn, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂, but the type of lateral roots evenly-distributed on primary root increases. The main type of RA is ＂lateral roots evenlydistributed on primary root＂, under the condition of N deficiency, and the types of RA turn out to be diversified. There exists a close relation between nutrient deficiency and RA changes. Owing to various forms of nutrient deficiency, correspondingly different types of RA have been produced.

介质转换对盆栽平邑甜茶(Malus hupehensis Rehd)的效应

利用一年生平邑甜茶（ＭａｌｕｓｈｕｐｅｈｅｎｓｉｓＲｅｈｄ）盆栽苗进行介质转换试验，研究对植株生长发育的影响，结果表明：由粘土转入沙壤土的，植株生长量有所下降，但器官发育质量提高，尤以叶绿素含量提高显著；沙壤土转入粘土的则相反。不论何种转换，根系生长量均不及对照，但由沙壤土转入粘土的，根系比对照减少更明显，说明粘土中建造起来的根系适应性更强。

Effects of Cinnamon Acid on Respiratory Rate and Its Related Enzymes Activity in Roots of Seedlings of Malus hupehensis Rehd.

This paper studied the effects of cinnamon acid treatments on the respiratory rate and related enzymes activity in the seedling roots of Malus hupehensis Rehd.It would provide information for understanding the mechanisms of inhibition damage caused by continuous cultivation of apple tree.20 mL of solution containing different concentrations of cinnamon acid was added into container with the tested seedlings.After treatment,the samples were taken periodically and the respiratory rates were measured by OXY-LAB oxygen electrodes under 25°C stable temperature and then the activities of related enzymes were measured.The rates of total respiration and other 2 pathways [tricarboxylic acid cycle （TCA） and pentose phosphate pathway （PPP）] appeared initially an increasing treads and late （on the 3rd d） began to decline.However,they again appeared an increase trend at the end period,on the contrast,the respiratory rate of embden-meyer- hot-parnas （EMP） pathway appeared a stead decline tread but it had a recover on the last day.The respiratory rate of total and 3 pathways were decreased under 125 mg kg-1 （soil）.The dynamic trends of the enzymes activities of pyrophosphate-dependent phosphofructokinase （PFK）,glucose-6-phosphate dehydrogenase （G-6-PDH） and malate dehydrogenase （MDH） showed similarly.In conclusion,treatments of certain concentration of cinnamon acid would inhibit the respiratory rate and related enzymes activity of roots of M.hupehensis Rehd.And the inhibition degrees were positively related with concentration of cinnamon acid treatments.

Relationship Between Polyamines Metabolism and Cell Death in Roots of Malus hupehensis Rehd. Under Cadmium Stress

The free putrescine （Put） content, the hydrogen peroxide （H202） content and the polyamine oxidase （PAO） activity in roots of Malus hupehensis Rehd. var. pinyiensis Jiang （PYTC） were significantly increased, and reached its peak at 1, 2 and 6 h, respectively, under cadmium treatment. The free spermine （Spin） and spermidine （Spd） contents were dramatically decreased, and reached the minimum value at 4-6 h, then remained relatively stable. The change in total free polyammes （PAs） content was consistent with that of free Put. The number of root dead cells was gradually increased after treatment for 24 h, and the typical characteristics of programmed cell death （PCD） were displayed at 48 h. Throughout the Cd treatment process, changes in PAs metabolism appeared to be prior to cell death increase, and the H2O2 content was always maintained at a high level. These results indicated that polyamines could initiate cell death by generating H2O2 in roots of Malus hupehensis Rehd. under CdSO4 stress.

用MaxEnt模拟湖北海棠(Malus hupehensis)地理分布

采用湖北海棠551个分布数据以及当前生物气候数据,用MaxEnt软件模拟了它的地理分布。结果显示:①潜在分布地区有巴基斯坦北部、印度北部、尼泊尔、不丹、缅甸东北部、越南西北部、广西北部、西藏南部及东南部、日本岛东南侧、朝鲜半岛中南部及沿海地区;河北东北部、山东半岛北部和辽宁南部,其中分布值在0.6～1的地区有不丹、韩国济州岛及附近岛屿和日本及附近岛屿。②分布记录非常少,但分布值已达0.6～1的地区有山西东南部、江苏省南通、四川雅安市汉源和山东崂山。③以分布值在0.6～1的地区来表示现实地理分布格局,自西东向分布为喜马拉雅南部,东南部-横断山-秦岭-巫山-长江中下游山地-武夷山-朝鲜半岛-日本岛。自北向南,北界在太行山南部,南界武夷山西南部。④Jackknife test检测表明干旱季节的平均温度对湖北海棠的分布增益贡献最大,本种自然分布于干旱季节平均气温在-10℃～15℃的地区。

NO_3^-/NH_4^+ ratios affect plant growth, chlorophyll content,respiration rate, and morphological structure in Malus hupehensis seedlings

Malus hupehensis （Pamp.） Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4＋ ratios （100/0, 50/50, and 0/100, molar basis） at total nitrogen （N） concentration of 8 mmoL L-1 in a nutrient solution on M. hupehensis seedlings. Plant biomass, NO3- and NH4＋concentrafion, chlorophyll con- tent, respiratory rate, and cellular structure were investi- gated. M. hupehensis seedlings at the NO3-/NH4＋ ratio of 50/50 had the highest level of fresh weight, dry weight, shoot length, and chlorophyll （a, b, and a ＋ b） content, but the lowest respiration rate in the leavesand roots. In addition, thickness and numbers of palisade and spongy tissue cells of the leaves were greater with this treatment than with other treatments. At the NO3-/NH4＋ ratio of 100/0, the leaves and roots had higher NO3- concentration and lower NH4＋ concentration. However, the opposite trend occurred at the NO3-/NH4＋ ratio of 0/100. Chloro- phyll （a, b, and a ＋ b） content was lowest at the NO3-/NH4＋ ratio of 100/0 than at the other ratios. At the NO3-/ NH4＋ ratio of 0/100, oxygen （02） consumption increased in the leaves and roots, and irregular epidermis and cortex cells were observed in the root apical meristematic and mature region. Our results indicated that the NO3-INH4＋ ratio at 50/50 was suitable for growth of M. hupehensis seedling to achieve the highest biomass production and efficiency.

Protein phosphorylation is involved in the water stress-induced ABA accumulation in the roots of Malus hupehensis Rehd

Water stress-induced ABA accumulation plays a key role in the root to shoot communication and/or the cell to cell signaling under the soil stresses. The signaling of the water stress itself that leads to the accumulation, however, is less known. In this study, we subjected the roots of Malus hupehensis seedlings to water stress treatment and investigated the ABA accumulation in relation to protein phos-phorylation. Our results showed that ABA accumulation could be substantially triggered in 40 min and reached 4 folds in 100 min after treatment with 30% PEG 6000 (polyethylene glycol). The water stress treatment also led to a substantial enhancement of total kinase activity, assessed with histone-111 as substrate, in 15 min and a maximum enhancement in 30 min before it declined to initial level. The Ca2+-dependent kinase activity showed a similar, if not more sensitive, trend. When the roots were fed with labeled 32P-ATP, water stress enhanced the labeling of proteins, which showed a maximum labeling at

Dopamine improves apple replant disease resistance by regulating physiological resilience and rhizosphere microbial community structure

Apple replant disease(ARD)is a complex agricultural problem caused by multiple stressors that can lead to increased reactive oxygen species(ROS)levels and limited nutrient utilization in plants.However,existing countermeasures cannot effectively address this challenge.Here,we used Malus hupehensis as a test organism to investigate whether the pleiotropic molecule dopamine can alleviate ARD using pot experiments.Exogenous application of 100μmol L-1 dopamine significantly promoted the growth of apple seedlings in the replanted soil,with a relative growth rate increase of 17.44%.Our results revealed two major pathways by which dopamine regulates ARD resistance in apple trees.First,dopamine effectively reduces the level of ROS and activates the expression of genes related to nitrogen(N)transport and metabolism.Among those genes,MdNLP5,MdNRT1.1,MdNLP2,MdNRT2.5,MdNLP3,MdNRT2.4,MdNADH-GAGOT,and MdFd-GAGOT were strongly regulated by dopamine.These regulatory effects promoted the uptake and utilization of soil N by the plants.Second,dopamine improved the physical and chemical properties,enhanced microbial community diversity,and promoted mutual cooperation between microbial communities in the soil.Furthermore,dopamine altered the microbial structure of rhizosphere soil(upregulating Clostridiales,Gaiellales,Sordariales and Mortierellales;downregulating Micrococcales,Longimicrobiales,Hypocreales and Cystobasidiales).Notably,dopamine significantly upregulated the abundances of Gaiella and Mortierella,both of which were positively correlated with soil urease activity,soil available N content,plant growth and N uptake.Dopamine also significantly downregulated the abundance of the plant pathogen Gibberella(by 11.71-fold)in replant soil.Our results provide insights into the mechanisms by which dopamine promotes ARD resistance,and can promote the sustainable development of the apple industry.

湖北海棠叶活性成分、功能特性及开发利用研究进展

湖北海棠[Malus hupehensis(Pamp.)Rehder]是药食两用植物,是湖北省西部重要的优势植物资源。近年来的研究表明,湖北海棠叶中富含黄酮类、多酚类、皂苷类等多种活性成分以及多种人体所必需的微量元素如硒、锌、铁等,具有改善认知功能、抗肿瘤、保护肝脏、雌激素样活性、降血糖、调血脂、抗氧化等功效,相关产品开发仍处于初级阶段。综述了湖北海棠叶的活性成分、功能特性及开发利用情况,以期为促进湖北海棠叶的广泛应用提供参考。

“金花菌”发酵对湖北海棠叶营养物质及生物活性的影响

为探究金花菌发酵对湖北海棠叶的影响,测定不同发酵时间下湖北海棠叶提取物中多糖、可溶性蛋白、多酚含量及DPPH清除率的变化。结果表明,湖北海棠叶发酵8 d的效果最佳,提取物中多糖、可溶性蛋白含量分别比发酵前降低了48.73%、43.68%;多酚含量比发酵前提高了79.63%(p<0.05),发酵后的湖北海棠叶提取物的DPPH清除率提高了62.40%。该试验为金花菌改善湖北海棠叶茶饮品质提供了理论依据。

湖北海棠叶多酚提取工艺优化及抗氧化活性研究

以湖北海棠叶为原料提取多酚。以多酚得率为指标,在单因素试验的基础上通过响应面法优化多酚提取工艺,并研究不同有机萃取物的多酚抗氧化活性。结果表明:最佳工艺条件为料液比1∶20(g/mL)、提取温度70℃、提取时间60 min、乙醇体积分数70%,在此条件下多酚得率为45.24%;乙酸乙酯萃取样品的多酚抗氧化活性最好,其DPPH·和ABTS^(+)·清除率的IC_(50)分别为0.05、0.47 mg/mL。

Isolation of phloridzin-degrading,IAA-producing bacterium Ochrobactrum haematophilum and its effects on the apple replant soil environment

We isolated and identified a bacterium that could produce IAA and degrade phloridzin in the rhizosphere soil of healthy replanted apple(the rootstock is M9T337 and the scion is Yanfu 3),providing a theoretical basis for reducing the obstacles associated with apple replant disease(ARD).Isolates were screened using Salkowski colorimetry and screening medium for phloridzin.The isolate of interest(W6)was identified as Ochrobactrum haematophilum based on morphological analysis,physiological and biochemical tests,and 16S rDNA sequencing.In a laboratory experiment,W6 produced auxin and promoted the growth of Arabidopsis thaliana roots,and its degradation rate of 100 mg.L^(-1 )phloridzin was 62.0%.In a pot experiment,W6 significantly reduced the phenolic acid contents of replanted soil,lowered the abundance of the harmful fungus Fusarium solani,and increased soil enzyme activities,thereby improving the micro-ecological environment of replant soil.W6 increased the root antioxidant enzyme activity and leaf photosynthetic pigment content of replanted Malus hupehensis Rehd.seedlings,effectively alleviating the decrease in net photosynthetic rate,transpiration rate and stomatal conductance caused by ARD.In a field experiment,W6 also promoted the growth of replanted apple(the rootstock is M9T337 and the scion is Yanfu 3)saplings.Therefore,W6 can promote apple growth and degrade phenolic acids,and it can be used as an effective treatment for the reduction of ARD.

连作对平邑甜茶幼苗叶片光系统Ⅱ、活性氧及抗氧化酶活性的影响

以盆栽平邑甜茶(Malus hupehensis)幼苗为试材,探讨连作对叶片光系统功能的伤害机制及对活性氧含量、抗氧化酶活性的影响。结果表明,连作条件下,平邑甜茶幼苗生物量减少,叶片净光合速率降低,PSⅡ受到损伤,其响应机制是:PSⅡ供体侧放氧复合体受到损伤,QA被过度还原,光合电子传递链中的QA-大量积累,PSⅡ反应中心和受体侧均受到显著性伤害,受体侧由QA向QB的传递受阻,电子传递链受到损害,大量能量积累导致光能过剩及活性氧浓度上升,对光系统造成氧化破坏,抑制光合作用。同时,以吸收光能为基础的性能指数降低,实际光化学效率减弱,PSⅡ激发能分配方式发生改变,植株叶片通过增加热耗散等消耗过多激发能来适应连作带来的胁迫环境。连作条件下,平邑甜茶幼苗叶片抗氧化酶系统与活性氧之间动态平衡被打破,加剧了脂膜过氧化程度,加重了对叶片的伤害。

间作白三叶促进苹果园土壤碳循环的机制

【目的】为了探明间作白三叶对苹果园土壤碳循环的影响机制。【方法】设置平邑甜茶幼树间作芳香植物白三叶处理,清耕为对照,在种植白三叶120 d后,分别取清耕处理平邑甜茶根际土(CF)、间作白三叶处理平邑甜茶根际土(TF)和白三叶根际土(TT),对土壤基本理化性质、微生物生物量、碳循环相关酶以及不同形态碳等养分指标进行检测。【结果】结果表明,间作白三叶能够显著降低平邑甜茶幼树根际土的pH和含水量,提高微生物总生物量,降低真菌和革兰氏阳性菌生物量,提高纤维素酶和脲酶活力,降低转化酶和淀粉酶活力,提高可溶性有机碳、易氧化有机碳含量和碳库活度指数,进而提高了全氮、全磷、全钾、碱解氮、速效磷、速效钾以及锰含量,降低C/P比以及钙和钠含量。【结论】结果表明,间作白三叶可以通过改变平邑甜茶幼树根际土微生物生物量来影响转化酶活力,从而提高土壤中易氧化有机碳含量,促进果树根际土壤碳循环和养分供应。

水杨酸诱导湖北海棠全长cDNA文库的构建及应用

以湖北海棠为材料,经水杨酸处理后,用改良CTAB法提取总RNA,纯化后构建全长cDNA文库,并进行PGIP基因的克隆.结果表明：（1）提取的总RNA无降解,无污染;mRNA弥散带主要集中在500～2 000 bp左右,没有rRNA残留.（2）ds cDNA弥散带主要分布于300～2 000 bp之间,PCR验证后片段大小分布于200～2 000bp之间,说明合成ds cDNA质量较好,成功地构建了全长cDNA文库.（3）通过PCR从该cDNA文库中克隆了PGIP基因,命名为MhPGIP,GenBank登录号为FJ449708;其核苷酸序列及推导氨基酸序列与苹果的一致性分别为98%和97%,该序列含有两个串联的亮氨酸重复序列.综上所述,构建的全长cDNA文库质量很好,该文库的建成可以用于今后抗病新基因的挖掘、克隆和利用,为苹果抗病机理的研究奠定基础.

生物炭和有机肥处理对平邑甜茶根系和土壤微生物群落功能多样性的影响

【目的】研究生物炭和生物有机肥处理对平邑甜茶根系及微生物功能多样性等指标的影响,为果园可持续发展提供参考依据。【方法】采用盆栽试验,添加生物炭和生物有机肥处理,分析不同生物炭和生物有机肥处理对植株根系、土壤微生物群落功能多样性的影响。【结果】施用生物有机肥和生物炭均可增加细吸收根量、细吸收根面积、土壤和根际可培养微生物量,提高土壤FDA酶活性和土壤微生物多样性,二者联合施用效果最佳。生物炭处理对细吸收根面积的改善效果优于生物有机肥处理,对土壤微生物多样性的改善效果则不如生物有机肥处理;10%生物肥+6%生物炭、10%生物肥+3%生物炭处理细吸收根面积分别是CK的6.6和10倍,10%生物肥处理是CK的2.5倍,6%和3%生物炭处理是CK的3.3和3.1倍,生物炭和生物有机肥处理土壤细菌数量为CK土壤的3.32—10.23倍,放线菌数量为CK土壤的1.2—1.97倍,真菌数量为CK土壤的3.24—5.26倍,根际放线菌数量在生物有机肥处理后最高,根际真菌数量则在3%生物炭处理后最高。【结论】增加土壤炭可以增加植株根系、土壤微生物多样性,有利于土壤肥力的保持和农业的可持续发展。

连作苹果土壤酚酸对平邑甜茶幼苗的影响

为探讨连作(重茬)苹果土壤中酚酸类物质的积累与苹果连作障碍的关系,在砂培条件下,取连作果园土壤中实际浓度的酚酸类物质处理平邑甜茶幼苗,探讨了连作2a的果园土壤中实测浓度的根皮苷、间苯三酚、根皮素、对羟基苯甲酸和肉桂酸对平邑甜茶幼苗根系线粒体指标、抗氧化酶活性、膜过氧化程度及活性氧(ROS)含量的影响。结果表明:连作土壤中实际浓度的5种酚酸类物质均使平邑甜茶幼苗生长受到抑制,根系受影响程度高于地上部分,表现为根冠比降低;线粒体膜通透性转换孔(MPTP)开放程度增大,线粒体膜电位降低,细胞色素Cyt c/a比值下降;降低了幼苗根系中超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,增加了过氧化氢(H2O2)、超氧阴离子自由基(O·-2)以及丙二醛(MDA)的含量。土壤浓度的5种酚酸类物质中,以根皮苷处理抑制效果最显著,间苯三酚处理抑制力最小。因此,根皮苷是引起苹果连作障碍的主要酚酸,实践中应重点考虑对根皮苷的降解以缓解苹果连作障碍。

平邑甜茶与扎矮山定子杂交后代的胚胎发育特征研究

利用激光扫描共聚焦显微镜(LSCM)和石蜡切片技术对平邑甜茶与扎矮山定子杂交获得的6个皱叶矮生型株系的胚胎发育过程及发育特性进行了观察与研究。结果表明:各皱叶矮生型株系在胚胎发育过程中表现出的特征大体相同,能进行正常的减数分裂并由功能性大孢子形成的有性胚囊表现出良好的发育趋势;在开花当天至花后2d,各株系的胚囊中均出现了精核或花粉内容物,观察到了部分株系的受精卵;在花后10d左右原胚形成。另外,在胚囊发育的特定时期,胚囊内细胞核的分布方式各株系间略有差异;在部分株系中观察到了少数多胚囊现象。综合而言,皱叶矮生型株系的胚胎发育特征是以有性生殖为主的生殖方式,与亲本扎矮山定子的胚胎发育特征较为一致;与亲本平邑甜茶不同,未出现平邑甜茶胚胎发育中的复杂现象并表现出较弱的无融合生殖能力。

铁锌互作对苹果锌、铁吸收分配的影响

【目的】分析锌在苹果营养器官之间的分配特性以及锌铁交互关系,解释锌铁吸收和分配机制,指导合理施用锌铁肥料。【方法】测定了盛果期‘红富’士苹果缺锌小叶病树和正常树夏季不同器官的锌铁浓度;以‘平邑甜茶’(Malus Hupehensis Rehd)为试材,采用正交设计方案、通过溶液培养法培养幼苗,分析不同锌铁供应水平下营养器官的锌铁分配特性及其锌铁交互作用关系。【结果】夏季,缺锌小叶病树各器官锌浓度低于正常树,铁浓度高于正常树。水培试验中,锌铁供应水平提高,‘平邑甜茶’幼苗各器官锌铁累积均显著升高,其变化幅度依次是根>茎>叶;锌铁交互对根、茎、叶锌、铁浓度影响的显著性逐渐降低,缺锌时各器官转运系数均高于1.00;在中、低锌水平下,根部锌、铁呈正相关,与大田结果一致,高锌处理则呈负相关;叶锌、铁均呈负相关。高铁水平下,根中锌铁正相关达极显著水平。【结论】在苹果树中,根系是锌的调节库,并在一定程度上调节树体的锌铁平衡;锌促进了铁在根系的累积,高铁对缓解锌的毒害起到一定的平衡作用;锌与铁在叶中相互抑制。

缺锌苹果树有机酸与锌吸收分配的关系

【目的】研究缺锌大田富士苹果树、苹果幼树和苹果树常用砧木平邑甜茶[Malus hupehensis(Pamp.)Rehd.]幼苗有机酸与锌吸收分配的关系,探讨有机酸影响锌吸收分配的作用机理。【方法】采用盛果期苹果树大田栽培、两年生幼树砂培和平邑甜茶幼苗溶液培养法进行试验。【结果】萌芽期小叶病树根系R0-1.5、R1.5-3、R3-5和R5-15锌和有机酸浓度呈现高于正常树的趋势,盛花期二者的浓度呈现低于正常树的趋势,生理落果期小叶病树根系R0-1.5、R1.5-3、R3-5和R5-15锌浓度显著大于正常树。与正常树相比,有机酸浓度小叶病树R0-1.5和R1.5-3中下降,R3-5和R5-15呈现升高的趋势,小叶病树根系锌吸收利用和有机酸代谢运输节奏发生改变,大田和水培试验发现,苹果树根系有机酸的水平与锌水平有关。缺锌导致盆栽幼树吸收根有机酸含量的升高。与pZn2+10.7相比,水培平邑甜茶pZn2+11.3处理1d,根中锌浓度显著下降,根和茎中草酸和苹果酸的浓度升高了1.09-1.35倍,有机酸向根系的分配比例增加,根系锌吸收速率显著增加;处理20d,平邑甜茶植株中的锌浓度和有机酸浓度及叶中有机酸的分配比例均显著下降。【结论】缺锌改变了苹果根系锌吸收和有机酸的代谢运输节奏,促进了有机酸向地下部的分配,有机酸在促进锌吸收分配方面起重要作用。