蓝莓果实不同发育期维管束解剖结构与水分运输变化

本文通过研究蓝莓果实不同发育期果实维管束解剖结构和水分运输变化,并结合果实生长动态与糖酸积累规律,揭示蓝莓果实不同发育期果实水分运输变化与果实生长和结构的关系。以‘蓝丰’蓝莓果实为试验材料,采用石蜡切片法、染料示踪法、品质分析和动态观察法,研究蓝莓果实不同发育期果实维管束水分运输规律。结果表明蓝莓果实横径呈双S曲线生长,在果实第1次快速生长期(Stage Ⅰ),果实维管束染色范围最大,水分运输速率也最大,但从果实进入生长停滞期(Stage Ⅱ)后,果实维管束水分运输速率下降,果实染色范围下降,在果实进入第2次快速生长期后(Stage Ⅲ),果实中央维管束水分运输速率比生长滞后期稍有增加,但心皮主维管束运输速率下降,在果实发育成熟期(Stage Ⅳ),果实维管束染色范围最小,果实维管束水分运输速率也最低。从果实解剖结构来看,在蓝莓果实整个生长过程中,维管束结构都保持完整,但中央维管束和心皮主维管束周围的薄壁细胞和果肉细胞在进入到第2次快速生长期(Stage Ⅱ)后发生破裂,同时该时期果实内糖分积累增加,有机酸含量下降。综上所述,在蓝莓果实发育过程中,维管束结构虽然保持完整,但周围薄壁细胞和果肉细胞的破裂能够引起果实水分运输速率下降。     

根域限制对葡萄果实发育和主要营养物质含量的影响

根域限制下葡萄果实在第二次快速生长期间糖分积累显著提高,有机酸含量下降更明显.随着果实pH值的升高,果实发育的第二次快速生长期间花青素含量迅速增加,而且根域限制的高于未受根域限制的.在果实的第二次快速生长期间葡萄果实中总蛋白和游离氨基酸含量迅速增加,也是根域限制的高于未受根域限制的.开花后30～40 d,维生素C含量达到最大,随后下降,果实发育后期又升高,而且根域限制的葡萄果实中的维生素C含量一直高于根域未受限制的.     

根域限制对葡萄根中IAA含量及其代谢相关基因表达的影响

以1年生"玫瑰香"葡萄为试验材料,进行根域限制栽培处理,以传统地栽为对照,研究根域限制对葡萄根系构型、细胞结构、IAA含量及其代谢和根系生长发育相关基因表达丰度的影响,以探讨根域限制栽培影响葡萄根系构型变化的内在机制.结果表明:(1)根域限制处理后,葡萄根系构型发生显著变化,主要表现在根尖处出现大量集群根、不定根持续发...     

红地球葡萄延后栽培成熟期水分运输研究

以3年生延后栽培的红地球葡萄为材料,在生育后期设置土壤水分处理控制在0.20(T_1)、0.25(T_2)和0.30 m~3·m~(-3)(T_3)左右,以果农常用的管理方法为对照(CK),在果实成熟期采用切片和田间树体茎流测定方法,研究果实水分运输结构变化和树体耗水状况。结果表明:(1)葡萄果实转色初期,果梗维管束的木质部结构完整且导管壁清晰可见;转色中期,果梗木质部部分导管壁变模糊,果刷中央维管束横切面积较转色前期变小;转色后期,果刷和果梗木质部导管壁模糊且破裂。(2)当葡萄果实可溶性固形物为7%时,果梗表皮细胞排列紧密且细胞间隙小,果刷维管束导管清晰可见;当可溶性固形物含量达到11%时,果刷中央维管束导管数量大于胚珠维管束,且分布不同;当可溶性固形物含量增加至15%时,果梗表皮细胞排列疏松,表皮细胞拉长,部分细胞发生破裂,果刷中央维管束和胚珠维管束的导管均出现解体。(3)9月11日左右,不同土壤水分处理(CK、T_1、T_2和T_3)茎液流达到最大值,峰值分别为3.51、3.95、4.37和4.59 d·L~(-1);葡萄转色中期,在低温影响下T_1的茎液流量整体显著低于T_2、T_3(P0.05),但与CK无显著差异;10月15日至10月26日无明显极端低温发生,不同处理树体茎液流量均呈下降趋势;11月下旬随着温度持续降低,树体各处理茎液流量迅速下降。研究发现,土壤含水量过高,低温发生时会造成树体茎液流量降低,增加土壤供水能够延缓葡萄可溶性固形物的积累,从而延缓葡萄成熟。     

灵武长枣果实发育结构特征研究

采用石蜡切片法,研究不同发育时期灵武长枣果实的结构特征。结果表明:(1)缓慢生长期细胞增长缓慢,外果皮细胞5~6层,表皮细胞由1层薄壁细胞构成,呈长矩形或长椭圆形,表皮细胞以内的薄壁细胞不断增生,形成内表皮细胞。果实体积增大伴随着空腔的出现,中果皮维管束数量多;(2)第一次快速生长期细胞增长迅速,表皮细胞排列疏松,中果皮中的空腔增大速度最快,维管束主要分布在靠近外果皮和内果皮的中果皮部位;(3)减缓生长期表皮细胞变成圆形或椭圆形等不规则形状,细胞排列松散,内表皮细胞形状、大小不一,细胞排列疏松。中果皮中的空腔继续增大,维管束数目逐渐减少,但变化幅度较小;(4)第二次快速生长期外果皮细胞层数减少到3~4层,表皮细胞和内表皮细胞难以区分,空腔随着果实体积的增大达到最大,许多细胞单列排成网状结构,形成更大的腔,果皮中的维管束分布最少。在灵武长枣果实发育过程中,不同发育时期的不同部位其果实的形态解剖特征不同。     

葡萄果实中的糖分积累和调控

文章介绍葡萄果实不同发育期糖分积累的特点.糖分积累的细胞学途径、共质体到质外体的转变过程和这两种途径的调控机制,以及根域限制栽培措施对葡萄果实糖分积累的影响和机制的研究进展.     

宁夏枸杞果实与种子形态发育初探

研究了宁夏枸杞不同发育时期果实和种子形态的变化特征及种子内胚的变化.结果表明:宁夏枸杞果实的生长发育曲线为花后8d以前为其第一次快速生长期,花后8～24 d为缓慢生长期,花后24～34 d是第二次快速生长期,属于典型的双“S”型.宁夏枸杞种子的生长曲线既不属于单“S”型,也不属于双“S”型,表现为果实的第一次快速生长期同样也是种子的快速生长期,但种子完成的生长比例快于果实完成的生长比例,此期种子内的胚乳生长快;当果实进入缓慢生长期,种子也表现出缓慢生长的特性,且种子长度和宽度的增加速率均显著低于果实第一次快速生长期种子的生长速率,此期种子主要进行胚的分化;在果实的第二次快速生长期,果实体积和重量迅速增加,而种子的长度和宽度增加很少,此期种子内仅胚进一步增大,从而反映出宁夏枸杞果实的发育与种子发育有一定的相关性.     

外源ALA对克瑞森无核葡萄叶片光合特性及果实品质的影响

以日光温室栽培的欧亚葡萄品种克瑞森无核为试验材料,在果实膨大期和始熟期采用不同浓度(50、100和150mg·L~(-1))5-氨基乙酰丙酸(ALA)喷施叶片和果穗,研究外源ALA处理对葡萄叶片光合特性、果实着色效果及果实品质的影响。结果表明:(1)各浓度ALA处理后葡萄叶片胞间CO_2浓度(Ci)、气孔导度(Gs)、蒸腾速率(Tr)、净光合速率(Pn)都有不同程度的增加,并以100mg·L~(-1) ALA处理效果最好。(2)50~150mg·L~(-1) ALA处理均能不同程度提高葡萄果皮花青素、叶绿素及类胡萝卜素含量,且各ALA处理的果实可溶性糖含量显著高于对照,但可滴定酸含量低于对照。(3)100和150mg·L~(-1) ALA处理能够显著改善果实成熟期的着色参数,且果实着色指数(CIRG)与花青素的积累呈现出良好的一致性。研究发现,在葡萄果实膨大期及始熟期喷施适宜浓度(100mg·L~(-1))ALA能够有效提高叶片光合性能,同时促进果实着色,显著改善果实外观色泽和果实品质。     

脱落酸对菜豆根溢泌的调节

1×10~(-6)MABA促进经去离子水或10 mM KCl溶液预处理启再置于去离子水中的菜豆根的溢泌量,促进K~ 、Cl~-、NO~3~-、H_2PO_4~-向木质部的运输速率和这些离子在溢泌液中的浓度。但对根系的K~ 离子吸收无促进作用,也无抑制作用。 ABA处理的菜豆根20分钟之内,~(86)Rb~ 的运输速率为对照的1.4倍,溢泌速率为对照的3.5倍。6-BA抑制溢泌速率和离子向木质部的运输速率,6-BA降低ABA的促进作用。 菜豆叶片上涂布的ABA(90μg/株)可以运向根部,使根部的ABA含量增加到对照的3.6倍。菜豆植株的地上部经干热风处理后,根内的ABA含量减少到对照的大约1/3,根的溢泌速率和K~ 的运输速率也随之减少。     

葡萄果实发育过程中果肉细胞超微结构的观察

用透射电镜观察了“巨峰”葡萄(Vitis vinifera×V.labrusca)果实3个发育时期中果肉细胞超微结构的变化。果实第一次快速生长期的果肉细胞超微结构表现出物质和能量代谢旺盛的特点。缓慢生长期的果实虽外部形态平静少变,但果肉细胞超微结构表现出深刻的变化:细胞核形状特化为裂瓣状是最显著的特点;线粒体数目丰富;粗面内质网槽库膨大形成的囊泡富集,出现向液泡汇融和向质膜靠近的现象;质膜内陷;液泡膜完整。另外,原生质也出现一些降解的现象。但总体结构特点表明果肉细胞在此期处于十分活跃的物质周转代谢和信息交换过程中。果实第二次快速生长期果肉细胞超微结构表现出衰老降解的特点,但线粒体结构依然完整,数量仍然丰富,原生质膜也保持了很好的完整性,这似乎与维持第二次快速生长或成熟有关。     

Relationships among Rhizosphere Oxygen Deficiency,Root Restriction,Photosynthesis, and Growth in Baldcypress (Taxodium Distichum L.) Seedlings

Seedlings of baldcypress (Taxodium distichum L.) grown in sealed containers containing nutrient solution were subjected to root-zone oxygen deficiency, physical restriction, and the combined stresses in a greenhouse. After six weeks of treatments (Phase I), half of the plants were harvested. The remaining half were allowed to continue (Phase II) under various treatments except plants that had restricted roots were freed thus allowing free expansion of roots into the nutrient solution. Oxygen deficiency and root physical restriction inhibited plant gas exchange parameters. Net photosynthetic rate (PN) was significantly higher in aerated unrestricted root (AUR) plants than in aerated root restricted (AR) plants and in anaerobic root unrestricted (FUR) plants than in anaerobic root restricted (FR) plants. After Phase I, FUR plants' shoot and root biomasses were 57.0 and 30.6 % lower than those of AUR plants, and AUR plants showed 3.3 and 3.8 times greater shoot and root biomasses than the AR plants, respectively. During Phase II, PN recovered rapidly in plants under aerated conditions, but not in plants under anaerobic conditions. The removal of physical root restriction under both aerated and anaerobic conditions resulted in rapid shoot and root growth in seedlings. Hence, root restriction or root-zone anaerobiosis, reductions in plant gas exchange, and biomass production in baldcypress were closely interrelated. In addition, root release from restriction was related to the regain of photosynthetic activity and biomass growth. The results support the previously proposed source-sink feed-back inhibition of photosynthesis in plants subjected to root-zone oxygen deficiency or physical restriction.     

Phloem unloading follows an extensive apoplasmic pathway in cucumber (Cucumis sativus L.) fruit from anthesis to marketable maturing stage

The phloem unloading pathway remains unclear in fruits of Cucurbitaceae, a classical stachyose-transporting species with bicollateral phloem. Using a combination of electron microscopy, transport of phloem-mobile symplasmic tracer carboxyfluorescein, assays of acid invertase and sucrose transporter, and [(14)C]sugar uptake, the phloem unloading pathway was studied in cucumber (Cucumis sativus) fruit from anthesis to the marketable maturing stage. Structural investigations showed that the sieve element-companion cell (SE-CC) complex of the vascular bundles feeding fruit flesh is apparently symplasmically restricted. Imaging of carboxyfluorescein unloading showed that the dye remained confined to the phloem strands of the vascular bundles in the whole fruit throughout the stages examined. A 37 kDa acid invertase was located predominantly in the cell walls of SE-CC complexes and parenchyma cells. Studies of [(14)C]sugar uptake suggested that energy-driven transporters may be functional in sugar trans-membrane transport within symplasmically restricted SE-CC complex, which was further confirmed by the existence of a functional plasma membrane sucrose transporter (CsSUT4) in cucumber fruit. These data provide a clear evidence for an apoplasmic phloem unloading pathway in cucumber fruit. A presumption that putative raffinose or stachyose transporters may be involved in soluble sugars unloading was discussed.     

核桃果皮的发育解剖学研究

核桃果皮的发育过程可分为３个阶段,发育时期：中、内三层果皮的界线不清,维管束处于发育初期;发育中期：随着中果皮最外侧两层石细胞的出现和薄壁组织细胞体积的迅速扩大以及维管束轮数的增加,使三层果皮具较明显的界面,发育后期：中果皮的维管束递增到４－５轮,     

Causes and effects of changes in xylem functionality in apple fruit

BACKGROUND AND AIMS: The xylem in fruit of a number of species becomes dysfunctional as the fruit develops, resulting in a reduction of xylem inflow to the fruit. Such a reduction may have consequential effects on the mineral balance of the fruit. The aim of this study was to elucidate the dynamics and nature of xylem failure in developing apples (Malus domestica) showing differing susceptibilities to bitter pit, a calcium-related disorder. METHODS: Developmental changes in xylem functionality of the fruit were investigated in "Braeburn" and "Granny Smith" apples by using a dye infusion technique, to stain the vasculature along the path of dye movement. The vascular bundles were clearly visible in transverse section when fruit were sectioned equatorially. The intensity of staining of the vascular bundles in the fruit was recorded at regular intervals throughout the season. Tissue containing dysfunctional bundles was fixed and embedded in wax for subsequent sectioning and examination. KEY RESULTS: As the season progressed, an increasing proportion of vascular bundles failed to show any staining, with the most marked change occurring in the primary bundles, and in nearly all bundles with increasing distance from the stalk end of the fruit. Decreased conductance in the primary bundles of "Braeburn" occurred earlier than in "Granny Smith". Microscopy revealed that the xylem in vascular bundles of the fruit suffered substantial damage, indicating that the mode of dysfunction was via the physical disruption of the xylem caused by expansion of the flesh. CONCLUSIONS: Results support the view that the relative calcium deficiency of apple fruit is due to a progressive breakdown of xylem conductance caused by growth-induced damage to the xylem strand in the bundle. The earlier onset of xylem dysfunction in the cultivar more susceptible to bitter pit suggests that the relative growth dynamics of the fruit may control the occurrence of calcium-related disorders.     

Pre-sowing magnetic treatments of tomato seeds increase the growth and yield of plants

The effects of pre-sowing magnetic treatments on growth and yield of tomato (cv Campbell-28) were investigated under field conditions. Tomato seeds were exposed to full-wave rectified sinusoidal non-uniform magnetic fields (MFs) induced by an electromagnet at 100 mT (rms) for 10 min and at 170 mT (rms) for 3 min. Non-treated seeds were considered as controls. Plants were grown in experimental plots (30.2 m(2)) and were cultivated according to standard agricultural practices. During the vegetative and generative growth stages, samples were collected at regular intervals for growth rate analyses, and the resistance of plants to geminivirus and early blight was evaluated. At physiological maturity, the plants were harvested from each plot and the yield and yield parameters were determined. In the vegetative stage, the treatments led to a significant increase in leaf area, leaf dry weight, and specific leaf area (SLA) per plant. Also, the leaf, stem, and root relative growth rates of plants derived from magnetically treated seeds were greater than those shown by the control plants. In the generative stage, leaf area per plant and relative growth rates of fruits from plants from magnetically exposed seeds were greater than those of the control plant fruits. At fruit maturity stage, all magnetic treatments increased significantly (P < .05) the mean fruit weight, the fruit yield per plant, the fruit yield per area, and the equatorial diameter of fruits in comparison with the controls. At the end of the experiment, total dry matter was significantly higher for plants from magnetically treated seeds than that of the controls. A significant delay in the appearance of first symptoms of geminivirus and early blight and a reduced infection rate of early blight were observed in the plants from exposed seeds to MFs. Pre-sowing magnetic treatments would enhance the growth and yield of tomato crop.     

High temperature stress of Brassica napus during flowering reduces micro- and megagametophyte fertility, induces fruit abortion, and disrupts seed production

High temperature stress (HTS), during flowering, decreases seed production in many plants. To determine the effect of a moderate HTS on flowering, fruit and seed set in Brassica napus, plants were exposed to a HTS (8/16 h dark/light, 18 degrees C night, ramped at 2 degrees C h-1, over 6 h, to 35 degrees C for 4 h, ramped at 2 degrees C h-1 back to 23 degrees C for 6 h) for 1 or 2 weeks after the initiation of flowering. Although flowering on the HTS-treated plants, during both the 1 week and 2 week HTS treatments, was equal to that of control-grown plants, fruit and seed development, as well as seed weight, were significantly reduced. Under HTS, flowers either developed into seedless, parthenocarpic fruit or aborted on the stem. At the cessation of the HTS, plants compensated for the lack of fruit and seed production by increasing the number of lateral inflorescences produced. During the HTS, pollen viability and germinability were slightly reduced. In vitro pollen tube growth at 35 degrees C, from both control pollen and pollen developed under a HTS, appeared abnormal, however, in vivo tube growth to the micropyle appeared normal. Reciprocal pollination of HTS or control pistils with HTS or control pollen indicated that the combined effects of HTS on both micro- and megagametophytes was required to knock out fruit and seed development. Expression profiles for a subset of HEAT SHOCK PROTEINs (HSP101, HSP70, HSP17.6) showed that both micro- and megagametophytes were thermosensitive despite HTS-induced expression from these genes.     

宽幅播种下基本苗密度对小麦旗叶光合特性及叶片和根系衰老的影响

为明确宽幅精播条件下小麦高产高效的适宜基本苗密度,于2018—2019年和2019—2020年在山东兖州大田试验条件下设置4种基本苗密度处理:90×10⁴株·hm^-2(D₁)、180×10⁴株·hm^-2(D₂)、270×10⁴株·hm^-2(山东高产田常用基本苗密度,D₃)、360×10⁴株·hm^-2(D₄),研究基本苗密度对小麦光合特性、衰老特性以及籽粒产量和水分利用效率的影响。结果表明: 与D₁、D₄处理相比,D₂处理显著改善了灌浆期间小麦旗叶光合特性,提高了旗叶和根系超氧化物歧化酶(SOD)活性、可溶性蛋白质含量,降低了旗叶和根系丙二醛(MDA)含量,延缓了旗叶和根系衰老;与D₁、D₃、D₄处理相比,D₂处理显著提高了0~40 cm土层小麦根长、根表面积和根体积。2018—2019年和2019—2020年,与D₁、D₃、D₄处理相比,D₂处理的籽粒产量分别提高11.8%、2.5%、6.4%和22.7%、5.7%、17.1%,水分利用效率分别提高9.2%、8.8%、14.2%和21.1%、6.2%、21.5%。综上,基本苗密度为180×10⁴ 株·hm^-2的D₂处理通过提高小麦灌浆期旗叶光合特性,改善小麦根系形态,延缓了植株衰老,籽粒产量和水分利用效率最高,是山东宽幅播种高产麦田的最优处理。     

The path of photosynthate translocation into citrus fruit

Abstract The path of [¹⁴C]photosynthate translocation into citrus fruit was examined to determine which anatomical and physiological features were involved in this process. Experiments were conducted during the final pre-harvest months of 2 years grapefruit crops (Citrus paradisi Macf. cv. ‘Marsh’). A source leaf nearest the fruit was exposed to ¹⁴CO₂ for 1 h + 5 h ambient air, followed by dissection of vascular and phloem-free tissues in the fruit quarter directly aligned with the source. Radioactivity in each tissue was quantified after separation and extraction in boiling 80% ethanol. Peel (flavedo+albedo) contained an average 35% of the label in the quarter fruit, but an additional 20% was localized entirely in dorsal vascular bundles along exterior walls of juice segments. Less [¹⁴C]photosynthate was recovered from other vascular tissues and was nearly absent from adjacent mature seeds. Radioactivity in the single layer of segment epidermis, however, averaged 17% of that in the quarter fruit. Juice tissues interior to this accumulated only 17% of the total. No phloem tissue was evident in either the segment epidermis or juice tissues, but over 70% of the [¹⁴C]assimilates in the latter were localized in thread-like stalks which attach juice vesicles to dorsal vascular bundles. In addition, labelled hexose/sucrose ratios in these structures increased with distance from the vascular bundle. The majority of photosynthates, therefore, entered citrus fruit via dorsal vascular bundles and were partially hydrolysed during slow transfer through non-vascular segment epidermis and juice stalks.     

施肥深度对矮化苹果15N尿素吸收、利用及损失的影响

以5年生烟富3/M26/平邑甜茶为试材,采用¹⁵N同位素示踪技术,研究表层(0 cm)、上层(20 cm)和中层(40 cm)3个施肥深度对矮化苹果¹⁵N 尿素吸收、分配及利用特性的影响.结果表明： 20 cm施肥处理的叶面积、叶绿素含量和叶片全氮含量显著高于0和40 cm施肥处理.不同施肥处理各器官从肥料中吸收分配到的¹⁵N量对该器官全氮量的贡献率(Ndff)存在显著差异,盛花期均以根的Ndff最高,多年生枝次之;新梢旺长期和花芽分化期根部吸收的¹⁵N优先向新生营养器官转运;果实膨大期各器官Ndff均达到较高水平;果实成熟期均以果实中的Ndff最高.果实成熟期不同施肥处理的¹⁵N分配率存在显著差异,20 cm施肥处理生殖器官和营养器官的¹⁵N分配率显著高于0和40 cm施肥处理,而贮藏器官的¹⁵N分配率显著低于0和40 cm施肥处理.在果实成熟期,20 cm施肥处理¹⁵N肥料利用率为24.0%,显著高于0 cm(14.1%)和40 cm施肥处理(7.6%),而¹⁵N损失率为54.0%,显著低于0 cm(67.8%)和40 cm施肥处理(63.5%).不同施肥深度土壤¹⁵N残留量随施肥深度的增加而显著增加.