Influence of the chemical composition of kenaf bast and core on the alkaline pulping response

The bast and core of kenaf,Hibiscus cannabinus L., have markedly different chemical components and alkaline cooking responses. The bast had about double the hot-water extractives content and only about half the lignin content of the core. The core contained a large amount of hemicellulose, mostly composed of xylan. The lignin structures of bast and core were also quite different: The former had a significant abundance of syringyl structures. Evidence showed that the bast was much more easily delignified than the core. When the bast and core were cooked together in alkaline condition, the pulp yields at the same kappa number were higher than those of the individual pulpings of bast and core. The bast-core pulping gave a positive effect on the yield of bast pulp in the sodaanthraquinone and kraft pulpings. On the other hand, kenaf was abundant in the hot water extractives. These extractives consumed alkali during cooking to a relatively large extent but acted as a protector of hemicellulose and slightly increased the pulp yields.Part of this paper was presented at the 48th and 49th Annual Meetings of the Japan Wood Research Society, Shizuoka, April 3–5, 1998 and Tokyo, April 3–5, 1999     

水分胁迫对红麻生理特性和产量的影响

水分胁迫下,红麻叶片水势降低,游离脯氨酸含量大幅度上升,过氧化物酶活性增强,蒸腾速率减慢,用水效率提高,绿叶面积和净同化率变小,生长受阻。以上变化随水分胁迫程度加重而加剧。复水后红麻各项生理功能恢复很快。反映了红麻是一种耐旱性很强的作物。在红麻旺长后期水分胁迫对营养生长及干茎和生麻产量的影响大于旺长前期。但旺长后期水分胁迫后有促进生殖生长的趋势。因此,根据红麻不同时期对水分胁迫的反应及收获对象不同而采取相应的水分管理技术是十分重要的。     

红麻杂种一代及其亲本的遗传组成与配合力分析

以13份红麻品种按NCⅡ（NorthCaralina）6×7交配设计组配42个杂种F1代与其亲本为材料,研究了红麻杂种一代及亲本材料9个主要经济性状的遗传构成及配合力,结果表明：除干皮精洗率外,其它8个性状组合间差异均达显著或极显著水平;遗传变异系数、遗传力、遗传进度均以单株子皮重、单株纤维重等产量性状较高,其余性状相对较低;南选、ID40、84K114－2等亲本一般配合力较好;84210×南选,ID40×917等组合具有高的特殊配合力,表现为强优势组合。     

红麻新品种浙红3号的特征特性与主要栽培技术

浙红3号是浙江省农业科学院作物所育成的红麻新品种,具有产量高,抗病性强,品质优,耐旱性强,适应性广等特点,是麻纺、造纸兼优的红麻新品种。     

人工老化对红麻种子活力及基因组DNA的影响

以3份红麻种子为材料,对人工加速老化后种子活力变化及基因组DNA的遗传完整性进行研究.结果表明:高温(44±1)℃、高湿(95％相对湿度)老化处理后,红麻种子的发芽势、发芽率、发芽指数和活力指数均随老化时间的延长而降低,活力下降过程不是等速率的,品种之间存在差异;利用筛选的23对RAPD引物对3份材料的对照和不同老化处理的DNA进行遗传完整性检测,83-20和台农1号的等位基因频率都是100％,未检测到差异;检测到辽55的等位基因频率为100.85％,存在差异,经t-测验差异不显著,表明人工老化对红麻种子基因组DNA的影响不显著,即老化对红麻种质遗传完整性无显著影响.     

红麻种质资源遗传多样性和分子鉴定技术研究——Ⅱ．红麻种质资源的遗传多样性和亲缘关系的AFLP分析

用扩增性酶切片段长度多态性(AFLP)分析了来源于世界不同国家地域的23份红麻种质资源和2份红麻近缘种玫瑰茄资源。用选取的6对引物组合获得了505条AFLP分子标记。结果认为AFLP分析是红麻品种鉴定和遗传关系检潮的非常有效的手段，同时根据AFLP分子标记检测到的红麻与玫瑰茄之闻的遗传差异支持了它们在分类学上的独立性。红麻种质资源的AFLP分析结果支持了红麻起源于非洲的假设，并证实了栽培红麻首先被引到亚洲．并进一步被传播到中北美洲。     

红麻施用稀土的效果与技术研究

通过对红麻施用稀土的生理效应及施用技术的研究表明,稀土能有效地促进红麻根系和纤维细胞发育,能有效地延长红麻生长后期的纤维积累时期,提高红麻抗逆能力,增加单株纤维产量,增产幅度1.37 % ～12.91 % ,并摸索出一整套简便易行的施用方法。生产上大面积推广应用14467 公顷,产生社会效益756.92 万元。     

红麻EST-SSR标记的开发及其多态性评价

红麻是最重要的自然纤维作物之一,然而SSR标记的匮乏限制了其遗传改良。本研究从红麻90 175个EST序列中挑出含有转录因子的EST,开发了94对SSR引物。以24份不同红麻种质资源的DNA为模板,利用9%非变性聚丙烯酰胺凝胶电泳检测多态性。结果表明,85对引物(占90.4%)至少在2个材料之间存在多态性,表明开发的EST-SSR具有很好的多态性。其中,三核苷酸重复所占比例最多,重复基元AAT和ATG的多态性较高。聚类分析表明,24份红麻种质资源的遗传相似系数变化在0.62~0.92之间,表现出丰富的遗传基础。这些结果不仅丰富了红麻的分子标记数量,而且为红麻的遗传分析提供资源。     

Nutrient content of Kenaf (Hibiscus cannabinus) at five growth stages

Abstract

Kenaf (Hibiscus cannabinus) grown during the wet season in the Ord Irrigation Area of Western Australia was sampled at five growth stages. The samples were separated into bark, wood, tops plus foliage and, where applicable, seed. Each fraction was analysed for zinc, manganese, iron, copper, sodium, potassium, calcium and magnesium by atomic absorption spectroscopy, and for nitrogen and phosphorus by colorimetry. Concentrations of these elements in each plant fraction are presented. Calculation of total above‐ground nutrient content of the crop indicated a high content of potassium throughout the growth cycle (up to .280 kg/ha), an initially high content of nitrogen (150 kg/ha) stabilising at a lower level (about 75 kg/ha) up to maturity, and an increasing content of zinc (150 g/ha to 350 g/ha) and calcium (65 kg/ha to 105 kg/ha) with age. A higher content of iron at maturity was also apparent (up to 1400 g/ha). A comparison with other reported data is made.     

红麻冠层发育 光能截获及群体生长的关系分析

红麻旺长期的冠层光能利用率以叶面积系数3.5最高,超过4则形成大量消费叶。小于2则冠层透光率过大,光能利用不足。旺长期后,由于红麻植株冠层顶部变尖,株型向有利于吸收更多光能的方向改变,叶面积系数在5以上能获得更大的光合产量。红麻的生长速率在旺长初至旺长中期上升最快,旺长中期与开花前都维持较高水平,但旺长后期(7/下—8/上),叶面积系数达最高4左右,个体与群体生长明显不协调,这以后中下部大量叶片转化为消费叶,从而导致8月下旬出现生长速率低谷。净同化率则在苗期、旺长中期及纤维积累盛期均较大,而旺长中期之前,由于新叶发生速度快,叶面积系数迅速上升及旺长后期叶片衰老,叶面积比下降幅度大,相对生长速率降低,这两个时期的净同化率相对较低。