腺嘌呤对菠萝快速繁殖的影响

以腺嘌呤(adenine,Ad)作为基本培养基(MS)的添加成分,进行菠萝的快速繁殖.以不加Ad作对照,结果显示不同浓度的Ad分别为1.0、2.0、3.0、4.0、5.0、6.0 mg·L-1对芽的分化及增殖均无显著促进作用.而在壮苗培养中,除Ad为1.0 mg·L-1外,其他各浓度均能极显著地提高幼苗的生长速率,而且在不同浓度间也出现了极显著差异.Ad在3.0～5.0 mg·L-1时,幼苗生长速率最快,可使出苗时间提前30 d以上.     

菠萝叶片色泽、色素及抗氧化活性的关系

以菠萝22个栽培品种的叶片为实验材料,测定其5种色泽参数（L^*、a^*、b^*、c^*和h^*值）、5种色素（叶绿素、类胡萝卜素、花青苷、类黄酮和总酚）含量及3种抗氧化活性指标（ABTS、DPPH自由基和亚硝酸盐的清除能力）,并进行相关性分析。研究结果显示,色泽参数a^*和h^*值可以作为菠萝叶片指示色泽、主要色素含量和抗氧化活性变化的重要指标;菠萝叶片主要色素组成是叶绿素、类黄酮和总酚,且含有少量的花青苷,几乎不含类胡萝卜素。相关性分析结果显示,菠萝叶片类黄酮和总酚含量均与3种抗氧化活性指标极显著正相关,而叶绿素含量与其它指标相关性未达到显著水平,类黄酮和总酚是菠萝叶片抗氧化活性的主要功效成分。     

Pineapple stem-derived bromelain based priming improves pepper seed protein reserve mobilization,germination, emergence and plant growth

Pepper seeds are slow to germinate and emergence is often non-uniform and incomplete, reducing gains from this cash crop. This study investigated the effects of pineapple stem- derived protease (stem bromelain) based priming on pepper seed germination in relation to reserve mobilization (specifically, proteins and amino acids), germination, emergence and plant growth. These parameters were compared across two controls, (1) unsoaked seeds and (2) seeds soaked in deionized water, and seeds soaked in pineapple stem bromelain crude extract (treatment). Seeds were soaked in bromelain crude extract possessing a proteolytic activity of 6.25 tU or deionized water (first control) for 3 h at 35 °C. Light microscopy revealed an abundance of protein bodies in the endosperm of the seeds prior to imbibition. When observed for a period of 96 h, these bodies were progressively degraded, with the rate of this degradation being fastest in bromelain-treated seeds. Quantitative analysis of protein levels confirmed this observation: 17.2 mg proteins/g FW at 120 h after priming in bromelain-treated seeds compared with 22.1 mg/g FW in controls (average). The bromelain treatment also increased levels of free amino acids from 3.9 mg/g FW in the controls to 4.6 mg/g FW after 120 h of imbibition. Germination and emergence percentages were initially higher in bromelain-treated seeds: 92.0% germination in bromelain-treated seeds vs. ~ 52.2% in the controls at 18 d; 100% emergence in protease-treated seeds vs. ~ 72.2% in the controls at 18 d. However, these parameters were comparable across the treatment and the controls at 28 d. Importantly, plant fresh and dry weights were significantly higher when seeds were primed with bromelain. The results suggest the use of bromelain extracts for priming pepper seeds based on their proteolytic activity, since germination is dependent on the availability of crude protein and essential amino acids. The benefits of bromelain seed priming appear to translate into improved seedling growth as well.     

Phenotypic and AFLP characterization of two new pineapple somaclones derived from in vitro culture

Fifty pineapple buds (cv. Red Spanish Pinar, donor) were collected from field-grown plants and cultured in vitro. Forty-three young pineapple shoots were obtained after 42 d of implantation. Shoots were micropropagated for 168 d to produce 24,768 shoots. Three hundred young leaves were randomly selected as explants for callus formation. Calli proliferated for 4 months. Five hundred calli were randomly selected and transferred to the plantlet regeneration medium. Four hundred twenty-seven in vitro-plantlets were obtained and later hardened ex vitro. Then, 387 plantlets were transferred to the field environment and asexually propagated for two generations (30 months). Only two phenotype variants were identified: P3R5 and Dwarf. A more detailed study was carried out to compare these two variants with the donor plant. The variant P3R5 showed differences in the number of slips and suckers, and in the presence of thorns in the leaves and in the fruit crowns. The somaclonal variant Dwarf, was different from the donor plant in regard with the plant height; the peduncle diameter; the number of shoots, slips and suckers; the fruit mass with crown; the number of eyes in the fruit; the fruit height and diameter; the leaf color; the plant architecture; the length of plant generation cycle; and the fruit color and shape. Both somaclonal variants showed different AFLP banding patterns in comparison with the donor cultivar.     

Effect of sucrose,inorganic salts,inositol, and thiamine on protease excretion during pineapple culture in temporary immersion bioreactors

Summary Although pineapple plants have been found to produce proteases ex vitro, most of the biotechnological investigations of this crop have been focused on propagation. The procedure involving the use of temporary immersion bioreactors is one of the most outstanding because of its high multiplication rate. We previously recorded specific protease activity in the culture medium during the pre-elongation step of this protocol. Therefore, we decided to modify the culture medium composition of this phase looking for an increase in protease excretion. Four independent experiments were performed to evaluate the effects of different levels of sucrose (0–350.4 mM), inorganic salts [0–200% Murashige and Skoog (MS) salt strength], inositol (0–2.20 mM), and thiamine (0–1.2μM). The following indicators were recorded: shoot fresh mass per bioreactor; and protein concentration, proteolytic activity, and specific protease activity in culture media. Specific protease activity, the most important indicator recorded, was highest with 262.8 mM sucrose, 100% MS salt strength, 0.3 μM thiamine and no inositol. Results shown here demonstrate that conditions adequate for propagation purposes (87.6 mM sucrose, 100% MS salt strength, 0.55 mM inositol, 0.3 μM thiamine) are not always adequate for protease excretion.     

Insufficient nitrogen supply from symbiotic fixation reduces seasonal crop growth and nitrogen mobilization to seed in highly productive soybean crops

Nitrogen (N) supply can limit the yields of soybean [Glycine max (L.) Merr.] in highly productive environments. To explore the physiological mechanisms underlying this limitation, seasonal changes in N dynamics, aboveground dry matter (ADM) accumulation, leaf area index (LAI) and fraction of absorbed radiation (fAPAR) were compared in crops relying only on biological N₂ fixation and available soil N (zero-N treatment) versus crops receiving N fertilizer (full-N treatment). Experiments were conducted in seven high-yield environments without water limitation, where crops received optimal management. In the zero-N treatment, biological N₂ fixation was not sufficient to meet the N demand of the growing crop from early in the season up to beginning of seed filling. As a result, crop LAI, growth, N accumulation, radiation-use efficiency and fAPAR were consistently higher in the full-N than in the zero-N treatment, leading to improved seed set and yield. Similarly, plants in the full-N treatment had heavier seeds with higher N concentration because of greater N mobilization from vegetative organs to seeds. Future yield gains in high-yield soybean production systems will require an increase in biological N₂ fixation, greater supply of N from soil or fertilizer, or alleviation of the trade-off between these two sources of N in order to meet the plant demand.     

Biochemical side effects of genetic transformation of pineapple

Evaluations were made during 30 days of in vitro-plantlet hardening. Transformed (bar, chitinase, ap24 transgenes) and non-transformed plantlets were compared. Both groups of plantlets were similar in regard with plant height and weight and peroxidase activity. However, statistical significant changes, caused by transformation, were recorded in levels of malondialdehyde, other aldehydes, chlorophyll (a, b, total), phenolics (free and cell wall-linked) and proteins.     

UV-B辐射对8个大豆品种种子萌发率和 幼苗生长的影响

在生长房5种(暗处、可见光、低、中、高强度紫外线-B)处理下,研究了8个大豆品种的种子萌发率和萌发后幼苗的生长状况。结果表明,暗处种子萌发率高于自然光和UV-B辐射的种子。UV-B辐射增强对大豆种子的萌发率没有显著影响,仅使部分品种的最大萌发率降低和导致部分品种达到最大萌发率的时间延长。幼苗的生长对增强的UV-B辐射非常敏感。使大部分品种的胚根变短增粗,这可能是植物激素作用的结果。大豆的叶绿素a、叶绿素b和总叶绿素含量明显受到UV-B辐射的抑制。UV-B作用能促进类黄酮在幼苗中的积累,紫外吸收色素的增设有利于提高对UV-B的抵抗力。UV-B辐射的这种效应及大豆品种间的差异在自然情况下会产生深远的生物学和生态学意义     

黄酮对刺五加嫩叶采后保鲜的研究

将 0、 0 .1、 1 .0、 1 0、 5 0 mg/ L浓度的黄酮溶液对剌五加进行叶面喷施 ,2 4 h后采嫩梢装塑料袋置于4°C冰箱中保存。分别取样分析保存 0 d和 6 d后叶片中的维生素 C的含量 ,以及保存 0 d和 1 2 d后叶片的水、可溶性糖、叶绿素和粗蛋白的含量 ,比较不同浓度的黄酮溶液处理对剌五加嫩叶中上述几种营养成分的分解情况。通过统计分析得出 :0 .1 mg/ L的黄酮溶液对延缓叶片中上述几种营养成分分解的效果最好 ,说明其对剌五加嫩叶采后保鲜有一定的作用     

Relative growth rates of leaves from soybean grown under drought-stressed and irrigated field conditions

Abstract. The relative growth rates and leaf area were graphed against leaf area, normalized with respect to final leaf area, to assess the applicability of the Lockhart cell wall expansion equation to soybean, Glycine max (L.) Merr., leaf development under field conditions. For leaves that had completed more than 20% of their growth, relative growth rates decreased linearly with an increase in the normalized leaf area, indicating that these leaves were undergoing strictly expansive growth. Drought stress significantly decreased the relative growth rate of these larger leaves. Small leaves which had completed less than 20% of their growth, were found to have highly variable relative growth rates. The large variability in relative growth rates indicated that the Lockhart cell wall expansion equation was inadequate to evaluate the growth of these young leaves. Drought stress had virtually no influence on the relative growth rates observed in the small leaves.     

三峡库区狗牙根对深淹胁迫的生理响应

选取三峡库区自然消落带野生狗牙根(XC)和非消落带野生狗牙根(FC)为研究对象,采用三重复裂区设计试验,主区为两品种,副区为6个不同深度水淹处理(0,1,2,5,10m和15m),分析了各处理植株几种酶活性和碳水化合物含量的变化情况.结果显示:①不同生境狗牙根受深淹胁迫后,丙二醛(MDA)都呈递增趋势,表明狗牙根在深淹胁迫下受到了不同程度的膜脂过氧化伤害,且随胁迫程度的增加受伤害增大.②超氧化物歧化酶(SOD)、过氧化物酶(POD)、谷胱甘肽还原酶(GR)活性和醇脱氢酶(ADH)活性较对照都有所增加;XC处理POD和SOD的最大值出现在5m深水淹处理,而FC出现在2m深处理,且XC 5米深淹处理GR值较对照和其他处理明显大;各受淹处理地下茎可溶性糖含量和淀粉含量都保持在较高水平.③从抗氧化酶活性和ADH活性的变化规律,以及淹水胁迫下植株的能量代谢情况,初步得出XC与FC都具有一定的耐淹性,且XC较FC具更耐深淹的能力,表明狗牙根作为禾本科植物遗传上具有一定的耐淹性,自然消落带狗牙根因长期生长于水淹胁迫环境,耐淹能力得到了进一步强化.从狗牙根对深淹胁迫的生理响应上,证明狗牙根是宜用于三峡水库消落带植被恢复的物种.     

Sensitivity of soybean leaf development to water deficits

Abstract. Drought effects on the final leaf area of individual leaves were hypothesized to depend on the leaf developmental stage at which drought occurred. To evaluate this hypothesis, final leaf area and cell number were measured for soybean ( Glycine max (L.) Merr.) leaves that were at different stages of development when single or cyclical drought treatment was imposed. Leaf emergence rate from the meristem, as depicted by changes in the plastochron index, was not as sensitive as leaf expansion to cyclical droughts. For leaf expansion, small leaves, once they emerged from the meristem, suffered larger decreases in growth than leaves undergoing rapid leaf area expansion. Decreases in final leaf area as a result of a cyclical drought were correlated with decreases in final cell number. Decreases resulting from a single 8-d drought were dependent on the age of the leaf at the time of drought, because small leaves were found to have proportionately larger decreases in final cell number and area than larger leaves. These results indicated that age-dependent leaf responses to drought are based on the relative activity of cell division and expansion at the time stress was imposed.     

Responses of soybean to oxygen deficiency and elevated root-zone carbon dioxide concentration

Root flooding is damaging to the growth of crop plants such as soybean (Glycine max L.). Field flooding for 3 d often results in leaf chlorosis, defoliation, cessation of growth and plant death. These effects have been widely attributed solely to a lack of oxygen in the root-zone. However, an additional damaging factor may be CO(2), which attains levels of 30 % (v/v) of total dissolved gases. Accordingly, the effects of root-zone CO(2) on oxygen-deficient soybean plants were investigated in hydroponic culture. Soybean plants are shown to be very tolerant of excess water and anaerobiosis. No oxygen (100 % N(2) gas) and low oxygen (non-aerated) treatments for 14 d had no effect on soybean survival or leaf greenness, but plants became severely chlorotic and stunted when the roots were exposed to no oxygen together with CO(2) concentrations similar to those in flooded fields (equilibrium concentrations of 30 %). When root-zone CO(2) was increased to 50 %, a quarter of soybean plants died. Those plants that survived showed severe symptoms of chlorosis, necrosis and root death. In contrast, rice (Oryza sativa L.) plants were not affected by the combination of no oxygen and elevated root-zone CO(2.) A concentration of 50 % CO(2) did not affect rice plant survival or leaf colour. These results suggest that the high susceptibility of soybean to soil flooding, compared with that of rice, is an outcome of its greater sensitivity to CO(2).     

石菖蒲根茎挥发油对稗、鳢肠和水稻的萌发与生长的影响

在实验室和温室条件下,用从石菖蒲根茎中提取的挥发油经减压蒸馏获得的组分四,对稗草、鳢肠和水稻的萌发与生长进行了生物学效应测试。结果表明,在低浓度时促进供试植物的萌发和生长,而在高浓度时则抑制萌发和生长。实验室培养皿条件下,50～400mg／L浓度抑制作用产生并逐渐增加,400mg／L以上达到90％或更高。但是,温室盆钵条件下,3000mg／L时才出现抑制作用,在1000mg／L以下均表现促进作用。     

星星草营养器官适应盐胁迫的结构特征

采用0．6％Na2CO3胁迫处理星星草[Puccinellia tenuiflora（Turcz．）Scribn．et Merr．]幼苗,光镜和电镜观察其根和叶的显微和超微结构。结果表明,星星草根的表皮向外突出形成密集的根毛;外皮层由1～2层细胞组成,排列较紧密;中皮层薄壁细胞排列疏松,形成发达的通气组织;内皮层呈典型的五面加厚;中柱鞘排列紧密,其壁加厚;初生木质部与初生韧皮部相间排列,初生木质部为5～7原型,中央为后生木质部导管,无髓存在。叶的表皮有表皮毛和丰富的蜡质层;叶上表皮泡状细胞数目较少,且深陷;气孔下陷,其下有较大的气室;叶脉有大、中、小3种维管束,大、中型维管束为C3型,小型维管束为C4型。星星草可能是介于C3和C4植物之间的类型,具有耐盐碱及耐干旱特征。     

Emergence and seedling growth of soybean cultivars and maturity groups under salinity

Soybean is an important agricultural crop and has, among its genotypes, a relatively wide variation in salt tolerance. As measured by vegetative growth and yield, however, the achievement or failure of a high emergence ratio and seedling establishment in saline soils can have significant economic implications in areas where soil salinity is a potential problem for soybean. This study was conducted to determine the effects of salinity, variety and maturation rate on soybean emergence and seedling growth. Included in the study were the variety ‘Manokin’; four near-isogenic sibling lines of the variety ‘Lee’ belonging to maturity groups IV, V, VI and VII; and the variety ‘Essex’ and two of its near-isogenic related lines representing maturity groups V, VI and VII, respectively. Field plots were salinized with sodium chloride and calcium chloride salts prior to planting. The soybeans were irrigated with furrow irrigation which redistributed the salts towards the tail ends of the field plots. Elevated soil salinity near the tail ends of the field significantly reduced soybean emergence rate, shoot height and root length. No significant reduction was found for emergence or seedling growth of variety ‘Manokin’ when the electrical conductivity of soil solution extract (ECe) was less than 3 dS m⁻¹. Soybean emergence and seedling growth was significantly reduced when soil ECe reached about 11 dS m⁻¹. Maturity groups V and VII of variety ‘Lee’ or V and VI of ‘Essex’ appeared to be more sensitive to salinity stress than other maturity groups. Salt tolerance of different genotypes and maturity groups should be considered, among other limiting factors, in minimizing salinity effects on soybean growth. This revised version was published online in June 2006 with corrections to the Cover Date.     

Physiological comparisons of two soybean cultivars differing in canopy photosynthesis. II. Variation in specific leaf weight,nitrogen, and protein components

Cultivar differences in canopy apparent photosynthesis (CAP) have been observed in soybean (Glycine max (L.) Merr.) but little is known about the physiological mechanisms which are responsible for such differences. This study was initiated to determine if variation in ribulose 1,5-bisphosphate carboxylase (RuBPCase) and soluble protein exists among cultivars which differ in CAP during reproductive growth. In addition, the relationship between specific leaf weight (SLW) and leaf protein was examined. Two Maturity Group VI cultivars, Tracy (high CAP) and Davis (low CAP), were grown in the field during 1979, 1980, and 1981 and in a greenhouse experiment. Leaves located at two canopy positions (topmost, fully expanded leaf and eighth node from the top) in 1979 and three canopy positions (those mentioned, plus the fourth node from the top) in 1980 and 1981 were sampled. Leaves at the two upper canopy positions exhibited greater SLW, RuBPCase m^–2, and soluble protein m^–2 than found at the eighth node down. Photosynthetic capacity of leaves at inner canopy regions was therefore affected by both light penetration into the canopy and leaf protein status. Over the three year period, the SLW was 23 percent and the soluble protein m^–2 leaf 21 percent greater in Tracy than in Davis. Although the trend in RuBPCase m^–2 leaf was not significant, it was consistently greater in Tracy in the field and greenhouse. No cultivar differences were observed when the proteins were expressed on a unit of leaf dry weight. The quantity of RuBPCase per unit leaf area was positively correlated with SLW with significant partial correlation coefficients of 0.62, 0.67, 0.35, and 0.82 for 1979, 1980, 1981, and the greenhouse study, respectively. Since these cultivars have similar leaf area indices during September, the greater SLW of Tracy is translated into more photosynthetic proteins per unit ground area and higher CAP rate.Abbreviations AP Leaf Apparent Photosynthesis - CAP Canopy Apparent Photosynthesis - DAP Days After Planting - DTT Dithothreitol - HEPES N-2-hydroethylpiperazine N-2 ethanesulfonic acid - LAI Leaf Area Index - LSD Least Significant Difference - PPFD Photosynthetic Photon Flux Density - PVP-40 Polyvinylpolypyrroledone (molecular weight, 4000) - RuBPCase Ribulose 1,5-bisphosphate Carboxylase - SLW Specific Leaf Weight     

The Effect of Potassium Nitrate on the Reduction of Phytophthora Stem Rot Disease of Soybeans, the Growth Rate and Zoospore Release of Phytophthora sojae

The effects of potassium nitrate (KNO₃) application on Phytophthora stem rot disease reduction of Glycine max (L.) Merr. cvs. Chusei-Hikarikuro and Sachiyutaka, and mycelium growth and zoospore release of a Phytophthora sojae isolate were investigated under laboratory conditions. The application of 4–30 m m KNO₃ prior to inoculation greatly reduced incidence of disease in the two soybean cultivars. Although a concentration of 20–30 m m KNO₃ led to a slight decrease in the growth rate of the PJ-H30 isolate on PDA medium, no significant relationship was observed between inhibition of the growth rate and disease reduction on application of 0.4–10 m m KNO₃. Disease suppression recorded in laboratory experiments using pathogen mycelium was due to the response of plant tissues rather than a direct inhibition of pathogen hyphal growth by the application of KNO₃. The extent of disease reduction was related to increased potassium concentration in plants of the two cultivars (except for some cases involving cv. Sachiyutaka), suggesting that differences existed between the two cultivars in terms of the effect of KNO₃ application on disease suppression. Scanning electron microscopic observation with fresh samples indicated marked accumulation of potassium at the penetration-stopping sites of P. sojae in the cortex layer of soybean plants treated with 30 m m KNO₃, compared with the non-treated control plants. The presence of 0.4–30 m m KNO₃ decreased the release of zoospores. These results suggest the possibility of applying a solution containing 20–30 m m of KNO₃ to decrease the incidence of disease in agricultural fields by the response of plant tissues to KNO₃.     

盐磷耦合胁迫下大豆的生长和钠、磷离子长距离运输

以2个耐盐性和磷效率有差异的大豆品种为材料,采用水培方法,探讨盐分与缺磷耦合胁迫对大豆生长和钠、磷离子长距离运输影响的结果表明:(1)盐分和低磷胁迫对大豆生长有交互作用,磷浓度相对较高(2MMOL·L-1)时大豆耐盐性降低;(2)钠由木质部的向顶部运输增加,钠在韧皮部的再分配增多;(3)盐胁迫下磷在木质部的运输能力提高,韧皮部中磷的再分配受影响不大;(4)磷盐互作对大豆生长的影响在品种之间无差异。