桃叶片中光合指标与树体矮化和生长的关系

以普通型“春艳”和短枝型“超红短枝”桃为试材,研究了2种类型桃叶片中各项生理生化指标与光合速率的关系,以期为桃树优良短枝型品种的选育和高效矮化密植提供理论依据.结果表明:桃叶片光合速率在普通型和短枝型间达到了差异极显著水平;净光合速率与光合有效辐射、蒸腾速率、叶片温度呈显著正相关;短枝型桃的光合速率、叶绿素含量、比叶重均高于普通型桃.     

半矮化型、紧凑型、普通型桃树枝条和叶片特征比较

利用紧凑型爱保太、普通型瑞光3号和半矮化种质SD-9238等3种生长型桃品种或株系的嫁接苗为材料,对其枝条和叶片的特征进行了调查研究。结果表明:(1)半矮化型SD-9238、紧凑型爱保太和普通型瑞光3号在一次枝长度上没有显著差异,但半矮化型和紧凑型的枝条较普通型短12.5%左右;节间长度方面,半矮化型<紧凑型<普通型,且差异均达到显著水平,一次枝节间长度差异达极显著水平;紧凑爱保太的分枝角度显著大于普通型和半矮化型。(2)萌芽率和成枝率均为紧凑型>普通型>半矮化型,萌芽率差异达显著水平,紧凑型的成枝率最高,与普通型、半矮化型差异达极显著水平,半矮化型成枝率比普通型低10.6%;半矮化型平均每个母枝萌发中长枝4.6个,低于普通型和紧凑型的6.5个和9.8个。(3)3种生长型的叶片长度没有显著差异,半矮化型叶片显著窄于其他类型;紧凑型的叶片干物质含量低于普通型和半矮化型,而后2者间没有明显差异。     

不同生长型桃光合作用特性研究

利用Li-6400光合作用测定仪,在大田条件下,对不同生长型桃的净光合速率(Pn)、光补偿点(Lcp)、光饱和点(Lsp)及叶绿素含量进行了研究。结果表明,不同生长型的桃树间以矮化型桃叶片的Pn值最高,其次是紧凑型桃,垂枝型和普通型桃的较低。不同品种的桃之间以中矮29的Pn值最高,为19.01μmol/(m2·s);其次是矮丽蜜和1-14;粉垂枝和早露蟠的较低,分别是12.76μmol/(m2·s)和12.70μmol/(m2·s)。Lcp以紧凑型桃最高,矮化型桃次之,普通型、半矮化型和垂枝型桃的品种间差别较大;Lsp以紧凑型桃最高,垂枝型桃次之,普通型桃最低。各生长型桃叶片单位鲜质量的叶绿素含量以紧凑型桃为最高,普通型桃最低。叶片单位鲜质量的叶绿素含量与Pn无显著相关关系。     

猕猴桃叶片10种矿质元素含量的动态变化、品种差异及相关性

为指导猕猴桃生产科学施肥,在陕西眉县以8个猕猴桃品种("海沃德""米良1号""徐香""金香""哑特""翠香""农大金猕""金魁")成年树(实生野生美味猕猴桃砧)为试材,连续两年于盛花期后15～170 d定期测定了叶片氮、磷、钾、钙、镁、铁、锰、铜、锌、硼等10种元素的含量,并对叶片各元素含量的生长期差异、品种差异及相关性进行统计分析。结果表明,品种对叶片磷、钾、钙、镁、锰和硼含量有极显著(p0.01)影响,对氮和铁含量有显著(p0.05)影响,对铜和锌含量无显著影响。"海沃德"叶片氮、磷含量较高,钙、镁含量较低;"米良1号"叶片氮、钙含量较高;"翠香"叶片钙含量较高,氮、磷、钾含量较低;"农大金猕"和"金魁"叶片氮、钾均较低。生长期对叶片各元素含量均有极显著影响。叶片氮、磷、钾含量从着果期至果实快速膨大期不断下降;在果实缓慢生长期和果实充实成熟期,氮持续下降,钾维持稳定,磷则有所回升。叶片钙、镁、铁、锰、锌、硼含量随着生长期的推进整体呈升高趋势,但不同元素初始升高和后期稳定的时间点略有差别。叶片氮含量与钾含量极显著正相关,与钙、镁、铁、锌、硼含量呈极显著负相关;磷分别与钾和铁呈显著正相关;钙、镁、铁、锰、铜、锌、硼等元素之间多呈极显著或显著正相关。     

钾素营养对油桃采果期树体营养状况的影响

以、7 a生曙光油桃为材料,在固定氮、磷比例基础上,通过改变钾肥用量,分析钾素营养对油桃采果期树体养分的影响.结果表明:油桃采果期枝、叶中可溶性糖和可溶性淀粉含量随钾用量增加而增加,且都显著高于对照.施钾有利于各器官中K的积累,且随钾用量增加,各器官中K含量相应增加.钾用量与油桃叶片和果实中N含量存在极显著正相关,与枝条中N含量、果实中Ca含量存在极显著负相关,与枝条中Ca、Mg含量存在显著负相关.     

山地苹果树更新修剪对树体营养及生长的影响

 在陕北黄土丘陵沟壑区以常规修剪为对照,探讨更新修剪对盛果期山地苹果树体营养和生长方面的影响。结果表明：更新修剪提高了叶片、枝条中的氮、磷、钾、钙含量,提高了果实中的氮、钾、钙含量,对果实中的磷和根系中的磷、钾无显著影响;降低了根系中的氮、钙含量;显著增加了长枝、中枝的比例,显著降低了短枝、叶丛枝比例,促进了枝条健壮发育。更新修剪增加了叶面积,提高了叶绿素、单果质量、果实维生素C和有机酸含量,对果实可溶性固形物、总糖、着色面积等无显著影响,提高了果实产量,极显著提高了果园的经济产值。     

不同砧木对烟富6苹果生长结果的影响

以短枝型烟富6苹果嫁接于不同矮化砧木上,研究不同砧木对嫁接组合的树体结构、叶片中矿质元素和果实品质的影响。结果表明,4年生树烟富6/M9T337自根砧嫁接组合比烟富6/M26中间砧/平邑甜茶基砧嫁接组合的树体冠幅大,中心干上侧分枝数量多,均差异显著;叶片中叶绿素总量,钾、锰、硼元素含量,单果重,一级果率,平均666.7m~2产量等指标高,均差异显著;叶片长度,百叶重,铜、锌元素含量,果实的果糖含量等指标低,差异显著;树高,干径,叶片宽度,叶片中氮、磷、钙、镁、铁元素含量,果肉硬度、可溶性固形物含量,可滴定酸含量,葡萄糖含量,总糖含量等多个指标均无显著性差异。综合评价M9T337自根砧嫁接烟富6的双矮组合生产性状优于中间砧M26/平邑甜茶嫁接烟富6的双矮组合,可在生产中推广应用。     

矮化密植苹果园土壤养分对果实品质的影响

以"金世纪"苹果为试材,对昆明市西山区团结街道办事处4个矮化密植苹果园的土壤养分状况、果实品质进行了调查、测定和分析。结果表明:4个矮化密植苹果园的土壤pH值平均为5.99;土壤有机质、碱解氮、速效磷、速效钾含量偏低,且果园之间各肥料的施用水平存在较大差异。土壤有机质与土壤各养分间均呈正相关,pH值与土壤各养分间呈负相关;不同土壤养分与果实品质也存在着相关性,其中单果质量与土壤有机质、全氮、全磷、全硼、碱解氮、速效磷、速效钾均呈正相关,与土壤pH值呈极显著负相关,可溶性固形物与pH值、有机质、全氮、速效钾呈正相关。     

广西富川纽荷尔脐橙园土壤和叶片营养状况研究与评价

对广西富川县60个纽荷尔脐橙园土壤和叶片样品进行营养成分检测分析。结果表明,土壤全部偏酸,有效硼普遍不足,有效锰不足的现象也较多,土壤有机质、碱解氮、有效磷、交换性镁和有效铜含量中等,有效铁含量较丰富,有效钾、有效锌、交换性钙含量高;叶片中磷、钾、铁、锰、镁含量基本处于适量至高量水平,氮也较丰富,钙不足现象明显,铜缺乏现象严重,全都缺锌;土壤pH值与交换性镁呈极显著正相关,与有效钾呈极显著负相关;土壤有机质与有效锌呈极显著正相关;土壤交换性钙与叶片钙含量呈显著正相关,土壤交换性镁与叶片镁含量呈显著正相关,土壤交换性钙、交换性镁与叶片锰含量呈极显著负相关。     

广西南丰蜜桔园土壤养分状况及其对果实品质的影响

2011年对广西南丰蜜桔园土壤样品、叶片样品和果实样品进行检测分析。结果表明,所检测的南丰蜜桔园土壤普遍偏酸,土壤有机质、有效磷、有效锌、交换性钙含量较高,碱解氮和速效钾含量中等,交换性镁、有效硼含量较低。柑桔叶片氮含量大部分低于适量范围,而磷、钾含量大部分处于适量范围,少量处于高量水平。柑桔园土壤pH值与土壤交换性钙和交换性镁分别呈显著和极显著正相关,土壤有机质与碱解氮呈显著正相关。土壤有效锌和速效钾含量与果实可溶性固形物含量呈极显著正相关,交换性钙含量与可溶性固形物呈显著正相关,而土壤pH值和有机质与可溶性固形物呈显著负相关。叶片中钾素、磷素与果实维生素C呈显著正相关。     

Fruit growth,cuticle deposition,water uptake,and fruit cracking in jostaberry,gooseberry, and black currant

Fruit cracking after rain limits the production of a number of crops, including some Ribes species. To gain a better understanding of the factors involved in cracking, fruit growth, deposition of the cuticular membrane (CM), water uptake and fruit cracking were studied in black currant (Ribes nigrum L. cv. Zema), gooseberry (Ribes uva-crispa L. cv. Rote Triumph), and jostaberry (Ribes nidigrolaria B. cv. Jostine). Fruit surface area and fresh mass increased continuously throughout development, whereas deposition of the CM was biphasic. CM mass per fruit increased rapidly up to 42, 41, and 49 days after full bloom (DAFB) in black currant, gooseberry, and jostaberry, respectively. Thereafter, CM mass per fruit remained constant in gooseberry and jostaberry or increased at a lower rate in black currant. The cessation of or reduced rate of CM deposition resulted in a decrease in CM mass per unit area in all berries. Elastic strain of the CM at maturity averaged 23.8% and 19.5% in gooseberry and jostaberry, respectively, and only 8.2% in black currant. Microcracks in the CM were observed first in gooseberry and jostaberry 64 DAFB, whereas there were no microcracks in black currant. Water uptake into mature detached berries was linear over 2 h of incubation. Rates of uptake were highest in gooseberry followed by black currant and jostaberry. Relative uptake was similar via the cut end of the pedicel (32.1%), the apex of the fruit (34.7%) and the fruit surface (33.2%). Rates of water uptake through the fruit surface were positively related to surface area. Average fruit water potential for black currant, gooseberry, and jostaberry was −2.14 ± 0.17, −1.24 ± 0.03, and −1.89 ± 0.20 MPa, while the permeability for osmotic water uptake was 7.7 ± 0.4 × 10⁻⁸, 5.2 ± 0.1 × 10⁻⁸, and 3.3 ± 0.3 × 10⁻⁸ m s⁻¹. Incubating whole fruit in deionized water for 72 h resulted in more cracked jostaberries (94%) than black currants (74%) or gooseberries (50%). A comparison of our findings in Ribes berries with published data for the sweet cherry drupe revealed that the berries fitted the relationships established in sweet cherry among fruit growth, cuticle deposition, strain of the cuticle, microcracking, permeability for osmotic water uptake, frequency of stomata and cracking. The Ribes berries were less susceptible to cracking than sweet cherry.     

Similitude,similarity, and scaling

An exceptionally rich and colorful literature, drawn in almost equal parts from pure mathematics, from the sciences, and from the technologies, has grown up over the years, which bear in different ways on the topics under discussion. It is the intent of the present paper to survey this far-flung literature, point out some of the commonalities and interrelationships which underlie it, and briefly indicate how it has been and can be applied. To my knowledge, this kind of review has not been attempted before.     

Climatic, landform, microtopographic, and overstory canopy controls of tree invasion in a subalpine meadow landscape, Oregon Cascades, USA

Tree invasions have been documented throughout Northern Hemisphere high elevation meadows, as well as globally in many grass and forb-dominated ecosystems. Tree invasions are often associated with large-scale changes in climate or disturbance regimes, but are fundamentally driven by regeneration processes influenced by interactions between climatic, topographic, and biotic factors at multiple spatial scales. The purpose of this research was to quantify spatiotemporal patterns of meadow invasion; and how climate, larger landforms, topography, and overstory trees have interactively influenced tree invasion. We combined airborne Light Detection and Ranging (LiDAR) characterizations of landforms, topography, and overstory vegetation with historical climate, field measurements of snow depth, tree abundance, and tree ages to reconstruct spatial and temporal patterns of tree invasion over five decades in a subalpine meadow complex in the Oregon Cascade Range, USA. Proportion of meadow occupied by trees increased from 8?% in 1950 to 35?% in 2007. Larger landforms, topography, and tree canopies interactively mediated regional climatic controls of tree invasion by modifying depth and persistence of snow pack, while tree canopies also influenced seed source availability. Landscape context played an important role mediating snow depth and tree invasion; on glacial landforms tree invasion was negatively associated with spring snowfall, but on debris flows tree invasion was not associated with snow fall. The importance of snow, uncertain climate change impacts on snow, and mediation of snow by interacting and context dependent factors in complex mountain terrain poses substantial hurdles for understanding how these ecotones may respond to future climate conditions.     

Wetlands, carbon, and climate change

Wetland ecosystems provide an optimum natural environment for the sequestration and long-term storage of carbon dioxide (CO₂) from the atmosphere, yet are natural sources of greenhouse gases emissions, especially methane. We illustrate that most wetlands, when carbon sequestration is compared to methane emissions, do not have 25 times more CO₂ sequestration than methane emissions; therefore, to many landscape managers and non specialists, most wetlands would be considered by some to be sources of climate warming or net radiative forcing. We show by dynamic modeling of carbon flux results from seven detailed studies by us of temperate and tropical wetlands and from 14 other wetland studies by others that methane emissions become unimportant within 300 years compared to carbon sequestration in wetlands. Within that time frame or less, most wetlands become both net carbon and radiative sinks. Furthermore, we estimate that the world’s wetlands, despite being only about 5–8 % of the terrestrial landscape, may currently be net carbon sinks of about 830 Tg/year of carbon with an average of 118 g-C m^?2 year^?1 of net carbon retention. Most of that carbon retention occurs in tropical/subtropical wetlands. We demonstrate that almost all wetlands are net radiative sinks when balancing carbon sequestration and methane emissions and conclude that wetlands can be created and restored to provide C sequestration and other ecosystem services without great concern of creating net radiative sources on the climate due to methane emissions.     

Up-regulation of mRNA expressions of fas,bcl-2, bim,bax, caspase-3, caspase-9, and bcl2l12 in K562 treated with bortezomib

AIM: To detect the treatment of K562 leukemia cells with bortezomib altering the expression of genes fas, bcl-2, bcl2l12, bim, bax, caspase-9 and caspase-3.METHODS: MTT assay was used to detect the inhibition of proliferation. Apoptosis was detected by Annexin-V staining and mitochondrial transmembrane potential (Δψm). RT-PCR was used to analyze the mRNA expressions of fas, bcl-2, bcl2l12, bim, bax, caspase-3 and caspase-9.RESULTS: Bortezomib caused a time- and dose-dependent inhibition of cell proliferation and IC50 of 24 h and 48 h were 161.41 nmol/L and 96.33 nmol/L, respectively. At the concentration of 104 nmol/L, bortezomib induced apoptosis in a time-dependent manner, including increasing annexin-V positivity and decreasing the Δψm. RT-PCR showed that bortezomib up-regulated the mRNA expression of fas, bcl2l12, caspase-9 and caspase-3, but mRNA expressions of bcl-2, bim and bax did not changed obviously.CONCLUSION: Bortezomib inhibits the proliferation of K562 and induces apoptosis, in which fas, bcl2l12, caspase-9 or caspase-3 gene is one of the main genes taking part in.     

Effect of paclobutrazol,prohexadione-Ca,deficit irrigation,summer pruning and root pruning on shoot growth,yield, and return bloom,in a ‘Blanquilla’ pear orchard

During the period 2001–2003 the performance of paclobutrazol, prohexadione-Ca, root pruning, summer pruning and deficit irrigation was studied with respect to a control in a Blanquilla pear orchard. Shoot growth, yield, fruit size, and return bloom were all evaluated.