Cell-wall lysing enzymes and products of cell-wall digestion elicit ethylene in citrus

Ethylene production was induced in Valencia oranges [ Citrus sinensis (L.) Osbcck] by injection of the fungal enzyme mixture Pectolyase ( Aspergillus japonicus ) which contains pectolytic enzymes into the peel. The mixture also stimulated production of 1-aminocyclopropane-1-carboxylic acid (ACC). Cycloheximide partially inhibited the Pectolyase-induced ethylene response. Pectin fragments, resulting from partial acid hydrolysis or Pectolyase digestion, caused an increase in ethylene production when injected into the peel of intact orange fruits. Pectic fragments produced by fungal enzymes are known to be elicitors of phytoalexins and in this study are shown to elicit ethylene in citurs.     

Proteolysis of ribulose-1,5-bisphosphate carboxylase/oxygenase in leaves of Citrus explants throughout the annual cycle and its regulation by ethylene

Leaf senescence and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBP carboxylase, EC 4.1.1.39) degradation in orange [ Citrus sinensis (L.) Osbeck cv. Washington Navel] explants have been investigated. Explants consisted of a segment of stem (ca 15 cm) and 5 mature leaves. In vitro RuBP carboxylase degradation was determined by culturing the explants in water for different periods of time (3 days usually) and quantifying the two RuBP carboxylase subunits in the extracts following sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In vitro RuBP carboxylase degradation was estimated by autodigestion of leaf extracts and SDS-PAGE. The extent of in vivo RuBP carboxylase degradation in explants cultured under 16 h light/8 h dark photoperiod varied throughout the year and showed a cyclic behaviour correlated with the growth cycle of Citrus. The highest proteolytic activity both in vivo and in vitro was found in explants made from April to August coinciding with the maximum vegetative growth period of the tree.
Leaf senescence and abscission could be retarded significantly at any time of the year by maintaining the explants continuously in the dark. Treatment of the explants in the dark with a continuous flow of ethylene enhanced both leaf abscission and rate of RuBP carboxylase degradation, proportionally to ethylene concentration (0.1-0.6 ppm). Ethylene-induced senescence of Citrus leaf explants in the dark appears to be a convenient model system to study the regulation of the proteolytic degradation of RuBP carboxylase.     

康定虫草主要寄主斜脉蝠蛾的研究

冬虫夏草是一味名贵的中药材.四川康定虫草的主要寄主斜脉蝠蛾翅面色斑多变异,可区分成“黑白斑”和“黄毛斑”两大色斑型.经交配试验和成虫形态特征(触角、口器、翅脉、前足、雌雄外生殖器和鳞片的超微结构等)的观察,证明为同一种,经鉴定是斜脉蝠蛾(Hepialus oblifurcus Chu et Wang)^**.     

湿地松与茶树间作根系分布状况的研究

湿地松(Pinus elliottii)是阳性乔木,茶树(Camellia sinensis)是阴性灌木。这两种树种间作,形成针阔、乔灌两层树冠结构的茶园复合生态系统,可以改善茶树生态条件,提高茶叶的产量和品质。但间作存在胁地现象。一般认为这是上层树木的过度遮荫和根系间的竞争造成的。为了解这两种树种根系的分布状况和相互关系,并为间作茶园的合理配置和加强这种茶园的耕作管理提供依据,我们进行了湿地松与茶树间作根系分布状况的研究。     

Net Mg2+ uptake in relation to the amount of exchangeable Mg2+ in the Donnan free space of ryegrass roots

Ammonium acetate and BaCl₂-triethanolamine were used to desorb Mg²⁺ from the root Donnan free space (DFS) of 23-d-old ryegrass (Lolium multiflorum Lam. cvs. Gulf and Wilo). Amounts of desorbed Mg²⁺ increased with the increase in Mg²⁺ activity of the nutrient solution. Slightly less Mg²⁺ was desorbed by Ba²⁺ than by NH₄ ⁺. Previously published data on short-term net Mg²⁺ uptake by intact 23-d-old ryegrass plants of the two cultivars were linearly related to the amount of exchangeable Mg⁺ desorbed from the root DFS (r²=0.90 and 0.81 for the desorption by NH₄ ⁺ and Ba²⁺, respectively). A sward of Mg²⁺ ions attracted to the negative charges of the cell surface is suggested to represent a part of a pool of Mg²⁺ available for active transport through the plasmalemma.     

可乐茄叶肉原生质体培养再生植株

本文报道茄属果树可乐茄（ＳｏｌａｎｕｍｑｕｉｔｏｅｎｓｅＬａｍ．）叶肉原生质体的分离、培养及植株再生。幼嫩叶片原生质体经酶游离、纯化后,以１×１０４个／ｍｌ密度培养于稍加改良Ｋ８ｐ（附加２,４－Ｄ０．５ｍｇＬ（－１）、ＮＡＡ１．０ｍｇＬ（－１）和ＢＡ０．５ｍｇＬ（－１））的培养基中,三天后开始分裂,一周分裂３—４次。一个月形成小细胞团,植板率为０．１—０．２％,小细胞团转培养于ＭＳ＋２,４－Ｄ０．５ｍｇＬ（－１）上增殖后进行分化。原生质体来源愈伤组织在ＩＡＡ（０．１—１．０ｍｇＬ（－１））与ＢＡ或ＺＴ组合的培养基中能诱导器官发生,芽分化率最高可达４２．９％;但ＩＡＡ、ＢＡ、ＺＴ三者一起使用未见任何器官分化。小芽在ＭＳ＋ＩＡＡ０．２ｍｇＬ（－１）中生根成植株。可乐茄叶肉原生质体的植株再生,可应用于育种和茄属植物遗传工程研究。     

伯乐树茎次生木质部结构的研究

利用光镜和扫描电镜对伯乐树（Ｂｒｅｔｓｃｈｎｅｉｄｅｒａ ｓｉｎｅｎｓｉｓＨｅｍ ｓｌ．）茎次生木质部的结构进行了研究。其主要特征为：（１）散孔材,有较明显的生长轮;（２）导管分子多为单穿孔板,少数为梯形复穿孔板,具螺纹加厚;（３）管胞、纤维－管胞和韧型木纤维同时存在,后两者有的具分隔;（４）木薄壁组织以轮界分布为主;（５）木射线多为大型异形射线,属异形ＩＩＢ型;（６）缺乏侵填体、树脂道及分泌细胞。对伯乐树科（Ｂｒｅｔｓｃｈｎｅｉｄｅｒａｃｅａｅ）的系统位置作了探讨。     

Novel Miscanthus hybrids: Modelling productivity on marginal land in Europe using dynamics of canopy development determined by light interception

New biomass crop hybrids for bioeconomic expansion require yield projections to determine their potential for strategic land use planning in the face of global challenges. Our biomass growth simulation incorporates radiation interception and conversion efficiency. Models often use leaf area to predict interception which is demanding to determine accurately, so instead we use low-cost rapid light interception measurements using a simple laboratory-made line ceptometer and relate the dynamics of canopy closure to thermal time, and to measurements of biomass. We apply the model to project the European biomass potentials of new market-ready hybrids for 2020–2030. Field measurements are easier to collect, the calibration is seasonally dynamic and reduces influence of weather variation between field sites. The model obtained is conservative, being calibrated by crops of varying establishment and varying maturity on less productive (marginal) land. This results in conservative projections of miscanthus hybrids for 2020–2030 based on 10% land use conversion of the least (productive) grassland and arable for farm diversification, which show a European potential of 80.7–89.7 Mt year⁻¹ biomass, with potential for 1.2–1.3 EJ year⁻¹ energy and 36.3–40.3 Mt year⁻¹ carbon capture, with seeded Miscanthus sacchariflorus × sinensis displaying highest yield potential. Simulated biomass projections must be viewed in light of the field measurements on less productive land with high soil water deficits. We are attempting to model the results from an ambitious and novel project combining new hybrids across Europe with agronomy which has not been perfected on less productive sites. Nevertheless, at the time of energy sourcing issues, seed-propagated miscanthus hybrids for the upscaled provision of bioenergy offer an alternative source of renewable energy. If European countries provide incentives for growers to invest, seeded hybrids can improve product availability and biomass yields over the current commercial miscanthus variety.     

不同发育时期中华绒螯蟹血淋巴渗透压的分析

中华绒螯蟹血淋巴渗透压随不同的生长阶段而异;不论是在淡水中,还是在不同盐浓度的海水中,都具有保持血淋巴高渗调节控制的能力。青春期前,6—9月份,血淋巴渗透压自390mOsm/Kg H_2O升至560mOsm/Kg H_2O;青春期后,9—12月份,自555mOsm/Kg H_2O升至656mOsm/Kg H_2O,但12月到翌年3月份却明显下降。雌蟹从淡水移入海水后的血淋巴渗透压调升速度,青春期后是青春期前的三倍左右。     

河蟹眼柄神经分泌细胞离子通道的膜片钳研究

采用全细胞膜片钳技术对培养12－24小时不同形态河蟹眼柄视节端髓X器官（MTXO）神经分泌细胞离子通道进行了研究。结果表明,河蟹眼柄MTXO中分布的A、B、C三种类型神经分泌细胞均可记录到由向电流和外向电流组成的正常全细胞电流。内向电流由高电压激活钙离子通道电流（Lca)和对TTX敏感钠离子通道电流（INa）组成。ICa的激活电压为－30mV,在0－ 20mV电压下达到峰值,在－40mV和－70mV保持电压下记录的ICa激活阈值、初始峰值及I－V曲线无明显差别。外向电流明显,幅值较大,包括对4－AP敏感的快速激活、快速失活钾离子通道电流（IA）和对TEA敏感的缓慢激活、缓慢失活钾离子通道电流（IK）。正常蟹种、二龄成蟹和早熟蟹种MTXO神经分泌细胞均表达电压门控钠、钾、钙离子通道,通道电流和电压特征无明显区别.