Can wild relatives of sorghum provide new sources of resistance or tolerance against Striga species?

Summary The genus Striga contains some of the most noxious parasitic plants, which have a devastating impact on cereal production in Africa; of most importance are Striga hermonthica and Striga asiatica . Complete resistance to infection by Striga species does not exist in cultivated cereals. Of great interest is the possibility that wild relatives of cereals may provide a genetic basis for resistance or tolerance to infection and may be of enormous value for the development of resistant crops. A wild relative of cultivated sorghum, Sorghum arundinaceum , demonstrated tolerance to infection by S. asiatica , with little impact of S. asiatica on host growth or grain production compared with the detrimental impact of the parasite on cultivated sorghum. Infection by S.hermonthica , however, had a significant influence on host performance for both wild and cultivated sorghum. Differences in host:parasite responses may be explained by the timing of parasite attachment and differences in host specificity for these two Striga species.     

月鳢消化系统形态及组织学的研究

对月鳢(Channaasiatica)消化系统的形态及组织学进行了研究。结果为:①肠道呈3次盘旋,肠长与体长之比为0 42±0 02;②随着发育和生长,消化道的粘膜层厚度及粘膜皱褶高度增大、粘膜皱褶及杯状细胞增多;③食道、胃、前肠、中肠和后肠的组织结构区别明显,且食道与胃在组织结构上具有一定的连续性和过渡性;④胰腺在肝脏中呈弥散性分布;⑤月鳢消化道的形态和结构与其食性高度相关。探讨了月鳢消化道形态结构与食性的关系,认为月鳢消化道具有典型的肉食性特征。     

Screening of Ethiopian sorghum (Sorghum bicolor) landraces for their performance under Striga hermonthica ‐infested conditions

Striga hermonthica is a major constraint to sorghum production and productivity in sub‐Saharan Africa, Ethiopia, in particular. The objectives of this study were to evaluate the performance of 49 sorghum genotypes based on their reaction to S. hermonthica and investigate the relationships among yield and Striga resistance traits, including the Striga emergence count, area under Striga number progress curve, area under Striga severity progress curve, grain yield under infested, grain yield under non‐infested conditions and relative yield loss. The genotypes differed significantly in all measured parameters under Striga‐infested and non‐infested conditions. The genotypes ‘Birhan’, ‘Gubiye’, Wolegie, Zegerie, Nechmashila I, Woftel, Tetron and Eyssa were identified as promising ones based on grain yield and Striga‐related traits. On the other hand, the genotypes Jamyo, Bobie, Gedido, Mankebar and Zengada had moderate Striga numbers with low relative yield loss as compared with susceptible checks. The most promising variety, Zegerie, Mankebar and Zengada, out yielded the standard resistant checks ‘Birhan’ and ‘Gubiye’ under Striga infestation. Ward cluster analysis grouped the 49 sorghum genotypes in to four distinct clusters under Striga‐infested conditions. All members of clusters II and III showed the highest yielding group with the lowest to moderate Striga number, while cluster IV supported the lowest yield with the highest Striga number. Significant negative correlations were observed between yield‐ and Striga‐related traits. Highly significant and strong correlations were observed among Striga resistance indices, indicating that any of the Striga resistance parameters can be used as an indicator of resistance. The wide variations in grain yield among genotypes under Striga‐infested conditions would be invaluable genetic resources for production in Striga endemic areas of Ethiopia.     

苦草对水中环境因子影响的日变化特征

在实验室模拟条件下，研究了沉水植物苦草对水体中环境因子影响的日变化特征。结果表明，苦草对水体中环境因子如pH值、溶解氧、电导率、总磷等有显著的影响，种有苦草的水中的电导率、总磷均明显低于无植物水体，溶解氧浓度和pH值明显高于无植物水体；另外，种有苦草的水体环境因子总体日变化趋势较明显，而无植物水体的环境因子基本处于相对稳定的状态，具有明显日变化特征的指标pH值、溶解氧的变化可能与苦草的光合作用有关，而总磷和电导率没有明显的日变化特征。试验结果为进一步研究沉水植物对水体中环境因子影响的日变化特征和影响机理，以及底泥磷释放可能存在的日变化具有一定的参考价值。     

江西道地药材车前子规范化栽培的配方施肥优化

[目的]优选车前子规范化栽培的施肥配方。[方法]通过二次旋转组合设计,建立车前子产量与氮、磷、钾和有机肥四因子的回归模型,利用DPS数据库系统确定最优施肥方案。[结果]车前子产量与氮、磷、钾和有机肥4因子的回归模型为:Y=2 937.44+105.46X1+17.06X2+62.69X3+265.18X4-251.17X21-80.01X22-150.62X23-55.67X24+22.75X1X2+22.75X3X4;以产量3 450 kg/hm2作为目标,配方施肥的系统优化方案为:施氮(尿素)247.65～314.81 kg/hm2;施磷(过磷酸钙)346.05～553.95 kg/hm2;施钾(K2SO4)213.3～340.425 kg/hm2;施有机肥(腐熟猪粪)32 737.5～35 782.5 kg/hm2。[结论]方程的拟合度较好,可以用来反映车前产量与氮、磷、钾和有机肥之间的关系。     

药用植物厚朴 TRAP 标记的开发和利用

【目的】探明种植密度对积雪草光合特性、产量和品质的影响,为积雪草的高产优质人工栽培 提供理论依据。【方法】采用单因素完全随机区组试验设计的方法,设置 3 万、6 万、12 万、16 万、25 万株 / hm2 5 个不同种植密度,利用便携式光合测定系统 Li-6400 测定积雪草叶片的光合参数,通过 HPLC 测定药材中 积雪草苷与羟基积雪草苷的质量分数。【结果】种植密度对积雪草的分枝数、单株干质量、茎粗、叶片厚度、 叶柄长、叶长与、叶宽等形态指标均无显著影响。随着种植密度的增加,积雪草叶片的叶绿素含量、净光合速 率（Pn）、气孔导度（Gs）、胞间 CO2 浓度（Ci）、蒸腾速率（Tr）均呈先升高后降低的变化趋势;Pn 在密度 12 万株 /hm2 时最高,为 15.24 μmol CO2 /（m2 ·s）,但与 6 万株 /hm2 密度无显著差异;在 6 万株 /hm2 密度下, 叶绿素 a、叶绿素 b、叶绿素总量、Gs、Ci、Tr 均达到最大值,均显著高于其他密度。积雪草的鲜质量、干质 量、折干率均随着种植密度的增加呈先升高后降低的变化趋势,以 6 万株 /hm2 最高,分别为 21.44 t/hm2 、4.20 t/ hm2 、19.60%,均显著高于其他密度处理。不同种植密度的积雪草苷与羟基积雪草苷总质量分数为 1.95%~2.73%, 均远超过《中国药典》2020 年版的规定（0.8%）;随着种植密度的增加,积雪草苷与羟基积雪草苷的质量分数 均呈先缓慢上升再下降的变化趋势,以 6 万株 /hm2 的积雪草苷与羟基积雪草苷质量分数总和最高、达 2.73%。 相关性分析结果显示,Tr 与药材鲜质量之间呈显著正相关,而药材干质量则与 Tr、Gs 等光合参数以及叶绿素总 量均呈显著正相关。【结论】积雪草大棚栽培最适宜的种植密度为 6 万株 /hm2 ,合理密植能有效增强积雪草的 光合特性和光合效率,进而提高药材产量与品质。     

Isolation and purification of active components from Centella asiatica and observation of their immunosuppressive effect

AIM：To isolate and purify the active components from Centella asiatica, and to observe their effect on the proliferation and apoptosis of mouse spleen lymphocytes. METHODS：Semi-preparative high-performance liquid chromatography was performed to further isolate and purify the extracts from Centella asiatica. The effects of the active components on apoptosis and mitochondrial membrane potential of the spleen lymphocytes were assessed by flow cytometry. The structures of the active components were identified by ultraviolet spectrometry, electrospray ionization negative-ion mass spectrometry, ［1H］ nuclear magnetic resonance (NMR) and ［13C］ NMR. RESULTS：The molecular weights of the active components from Centella asiatica, named compound I and compound II, were 302 and 286, respectively. The compound I and compound II from Centella asiatica significantly inhibited the proliferation, promoted the apoptosis and reduced the mitochondrial membrane potential of mouse spleen lymphocytes. Compound I and compound II were identified as quercetin and kaempferol. CONCLUSION：The compound I and compound II from Centella asiatica show antiproliferative and immunosuppressive effects on mouse spleen lymphocytes by promoting apoptosis and reducing mitochondrial membrane potential.     

Virulence characteristics of a new race of the parasitic angiosperm,Striga gesnerioides,from southern Benin on cowpea (Vigna unguiculata)

An in vitro growth system was used to determine the virulence of two samples of Striga gesnerioides from Zakpota in southern Benin. Cowpea variety B301, previously considered resistant to all races of S. gesnerioides, was susceptible to both samples of the parasite. Two other cowpea varieties, 58–57 and IT81D-994, were totally resistant. Resistance in 58–57 was associated with a hypersensitive necrosis of infected roots, whilst IT81D-994 supported production of small S. gesnerioides tubercles with stems which failed to develop. Striga gesnerioides from southern Benin is the fourth race of the parasite to be identified, and the first with virulence on variety B301. The implications for breeding cowpeas with resistance to S. gesnerioides are discussed.Abbreviations IITA International Institute of Tropical Agriculture - LARS Long Ashton Research Station - SAFGRAD Semi-Arid Food Grain Research and Development     

Pattern analysis of genotype × environment interaction for striga resistance and grain yield in African sorghum trials

The parasitic weed Striga hermonthica (Del.) Benth. seriously limits sorghum [Sorghum bicolor (L.) Moench] production in Sub-Saharan Africa. As an outbreeder, S. hermonthica is highly variable with an extraordinary capacity to adapt to different hosts and environments, thereby complicating resistance breeding. To study genotype x environment (G x E) interaction for striga resistance and grain yield, nine sorghum lines, 36 F₂ populations and five local checks were grown under striga infestation at two locations in both Mali and Kenya. Mean squares due to genotypes and G x E interaction were highly significant for both sorghum grain yield and area under striga severity progress curve(ASVPC, a measure of striga emergence and vigor throughout the season). For grain yield, the entry x location-within-country interaction explained most of the total G x E while for ASVPC, entry x country and entry x location-within-country interactions were equally important. Pattern analysis (classification and ordination techniques) was applied to the environment-standardized matrix of entry x environment means. The classification clearly distinguished Malian from Kenyan locations for ASVPC, but not for grain yield. Performance plots for different entry groups showed differing patterns of adaptation. The ordination biplot underlined the importance of entry x country interaction for ASVPC. The F₂ derived from the cross of the striga-resistant line Framida with the striga-tolerant cultivar Seredo was the superior entry for both grain yield and ASVPC, underlining the importance of combining resistance with tolerance in striga resistance breeding. The observed entry x country interaction for ASVPC may be due to the entries' different reactions to climatic conditions and putative differences in striga virulence in Mali and Kenya. This revised version was published online in August 2006 with corrections to the Cover Date.