The roles of light and pericarp on seed dormancy and germination in feral Raphanus sativus (Brassicaceae)

The timing of seed germination may determine the success of a weed species in an agroecosystem, and its expression is modulated by environmental conditions, but also by seed physiology and anatomy. The aims of this study were to investigate the roles of light, pericarp, dry storage and cold stratification on seed dormancy and germination in feral radish, a troublesome agricultural weed in temperate zones of the Americas that reduces crop yields. To this end, we used isolated intact pods and extracted seeds to test germination over time under contrasting temperature, light and storage conditions. Here, we showed that fresh seeds were non‐dormant, but that light and the presence of the pericarp reduced germination, especially under low temperatures. The pericarp reduced the final water content absorbed by seeds inside pods and decreased absorption/dehydration rates. The pericarp showed several small lignified cell layers in the endocarp, and x‐ray images displayed the lack of space between the partially embedded seed and the endocarp. Dry storage and cold stratification were ineffective in breaking the dormancy imposed by the pericarp. The apparent requirement for darkness and the mechanical restriction of the pericarp may have the potential to induce dormancy, spreading the timing of seed germination over a more extended period and hindering the control of feral radish.     

草莓摘叶处理对果实芳香物质的影响

 对草莓(Fragaria×ananassa Duch．)‘哈达’品种坐果后植株进行摘叶处理，对成熟果实的糖类和芳香物质含量进行了测定分析，结果表明：不摘叶、摘1/3叶和摘2/3叶3个处理果实GC/MS分析分别检测出43、33和37种芳香物质成分。随摘叶程度加重，芳香物质成分中酯类的相对含量呈下降趋势，而醛类的相对含量呈上升的趋势；2，5-二甲基-4-甲氧基-3(2H)-呋喃酮的相对含量明显降低；果糖和总糖含量显著降低。     

热研4号王草干燥特性的试验研究

在将热研4号王草调制成青贮饲料或干草的加工中,干燥是一个关键性环节,也是发展热研4号王草产业的瓶颈问题。为此,采用快速薄层干燥的试验方法,研究热研4号王草的含水量与干燥时间、干燥介质温度两者之间的关系,并分析影响其营养成分的因素。结果表明:热研4号王草的干燥最佳介质温度为150°～180℃,鲜草刈割后必须在24h内进行快速干燥。     

Relationship between light,fruit and leaf mineral content with albinism incidence in strawberry (Fragaria x ananassa Duch.)

A study was conducted in strawberry to establish a relationship between shading, mineral nutrient of leaves and fruits with albinism incidence. Plants grown under shade produced albino fruits in higher proportion than those grown in open fields. Similarly, plants under shade produced smaller sized fruits and have lower fruit yield. Among cultivars, Etna had highest incidence of albinism (49.6%) and Sweet Charlie the lowest (14.4%). Dry matter content (%), concentration of five major nutrients, viz. N, P, K, Ca, Mg, S and N:Ca and K:Ca nutrient ratios did not differ significantly in the leaves of plants producing normal or albino fruits. However, in contrast, the concentration of K was notably higher (1.97 mg g⁻¹ fresh tissue weight) and that of Ca was lower (0.098 mg g⁻¹ fresh tissue weight) in albino fruits than normal ones. Consequently, the ratios of N:Ca (11.34) and K:Ca (20.08) were higher in albino fruits than normal ones. Cultivars also differed widely in respect to dry matter (%), mineral content and nutrient ratios. Thus, it appears that lower light intensity favours the development of albinism in strawberry, and it seems that calcium is not the basic cause of albinism, but increased vigour associated with overuse of N and K might be positively associated with it.     

The effect of strain, growth stage, and cultivating condition of Ganoderma lucidum on 5α-reductase inhibition

The inhibitory effects of 102 methanol extracts of 40 mycelia, 9 culture fluids, and 53 fruiting bodies of 40 strains of Ganoderma lucidum on 5-reductase were investigated. The methanol extract of the fruiting body of each strain was found to show the strongest 5-reductase inhibitory activity among the extracts tested.     

撑绿竹出笋规律探析

对水富县引种的撑绿竹出笋规律进行了研究,结果表明:撑绿竹出笋期在5月下旬至9月下旬左右;退笋多出现在末期;高生长的logistic曲线模型为:H=867.168/(1 e4.793-0.735);昼夜总生长量达7.09cm,夜间生长量几乎是白天生长量的1.76倍.     

Simple method for synthesizing phenolicβ-O-4 dilignols

A modified synthetic method for phenolic-O-4 lignin substructure model dimers was developed involving protection of the phenolic hydroxyl group of acetophenons with benzoyl chloride, bromination with 4-dimethylaminopyridiniumbromide perbromide, condensation with phenols in the presence of 18-crown-6-ether, condensation with paraformaldehyde, reduction with NaBH₄ and debenzoylation. This method results in shorter reaction times and increasing yields without the application of strict anhydrous and drastic conditions or chloric solvents. This alternative route could be applied to the-O-4 dilignol syntheses of four combinations of guaiacyl and syringyl derivatives.     

Absolute configuration of arylglycerol-β-aryl ethers obtained by asymmetric reduction of the correspondingα-ketonic compound with intactFusarium solani cells

When (±)--oxo-guaiacylglycerol--(vanillic acid) ether (1) is degraded byFusarium solani M-13-1, the-ketone is initially reduced to giveerythro andthreo guaiacylglycerol--(vanillic acid) ethers (2), arylglycerol--aryl ethers, both of which are enantiomerically pure. The absolute configuration in each2 was determined by Mosher's method; the products were converted to,-di-(R)--methoxy--trifluoromethylphenylacetates (MTPA esters) (3) oferythro (-)- andthreo (+)-veratrylglycerol--(methyl vanillate) ethers (3), whose¹H nuclear magnetic resonance (NMR) spectra were examined and compared with those of four di-(R)-MTPA ester (3) diastereomers from chemically synthesizederythro (±)-3 andthreo (±)-3. To assign the- and-MTPA-OCH₃ peaks, the¹H NMR scans of several compounds that have substructures of 3 and their 3,4,5-trimethoxyphenyl analogues were examined. When a racemic alcohol reacts with (R)-MTPA to give a pair of (R)-MTPA ester diastereomers, the value was defined as the absolute value of the difference in the¹H chemical shifts of the peak between the diastereomers. It was found that the values of-MTPA-OCH₃ were larger than those of-MTPA-OCH₃ owing to a shielding effect of the veratryl ring located on the-MTPA-OCH₃, and that the-MTPA-OCH₃ peaks in the 3,4,5-trimethoxyphenyl compounds shifted downfield relative to those in the veratryl compounds. On the basis of the¹h NMR data of (R)-MTPA esters, the absolute configuration of the four chemically prepared diastereomers (3) were determined. The catabolicerythro 3 [fromerythro (-)-3] andthreo 3 [fromthreo (+)-3] were identical to (R, S, R)-erythro 3 and (R, S, S)- threo 3, respectively. An hydrogen species in the fungal reduction would attack the-ketone fromre-face of both (R)-1 and (S)-1, givingerythro (S, R)-2 andthreo (S, S)-2, respectively.Part of this paper was presented at the 33rd Lignin Symposium, Tsukuba, November 1988     

Preparation of novel reagents 4-alkoxytrityl chlorides and their reaction with methyl Α-d-glucoside

A series of novel 4-O-alkoxytrityl chlorides (1) with different chain lengths was synthesized as a novel reagent for obtaining 6-O-alkylated cellulose with high regioselectivity via trityl groups in one reaction step without the use of any protective groups. These chlorides were reacted with methyl -d-glucoside, which was used as a model compound, to examine the reactivities toward the primary hydroxyl groups of cellulose to afford a series of 6-O-alkylated methyl -d-glucosides in high yields. The product compounds were found to have interesting solubilities and thermal properties. Thus, newly prepared trityl chloride derivatives were found to be useful regioselective derivatization reagents on the primary hydroxyl group in carbohydrates, especially in cellulose.