芥蓝游离小孢子培养及植株再生研究

对12个基因型的芥蓝进行了游离小孢子培养及植株再生研究.结果表明:供体基因型对诱导胚胎发生至关重要;最佳热激温度为32℃,24h;单核靠边期到双核期的小孢子最适合进行胚胎诱导;NLN培养基中的最佳蔗糖浓度为130 g·L-1;添加活性炭可以提高成胚速度和质量;15～25 ℃的供体植株生长的环境温度决定着游离小孢子培养的成败,将子叶型胚胎转移到MS固体培养基上可直接发育成植株.     

药用植物半夏细胞悬浮培养和植株再生体系建立研究

为了建立甘肃产药用植物半夏的细胞悬浮培养和植株再生体系,通过对其不同外质体筛选、愈伤组织诱导和悬浮培养的愈伤组织类型、激素水平、起始密度、震荡速率等影响因素以及细胞生长状态、生长曲线和pH值变化等指标的研究.结果表明:以叶柄为外质体,选择"松散型"愈伤组织和2×105个/mL的起始培养密度,在附加2,4-D 2.0 mg/L BA 0.5 mg/L NAA0.5 mg/L的1/2 MS培养基上培养,温度(23±2)℃,转速90 rpm,pH值6.0,黑暗培养为最适悬浮培养体系;经检测细胞生长曲线呈"S"型,培养液pH随着细胞的生长先上升后下降,18 d时细胞基数达到最大值;悬浮继代培养后,通过降低或停止震荡转速,在添加BA 0.5 mg/L NAA0.5 mg/L的MS液体和固体培养基上可诱导分化出芽和根,进一步形成完整的植株.     

藿香植物组织培养技术研究

选用藿香健壮枝条和叶片作为试验材料,进行组培技术的研究.结果表明:藿香取材季节以夏季较好,适宜的外植体种类为茎段.诱导愈伤组织形成的激素组合为6-BA 1.0mg/L NAA 0.3 mg/L 2,4-D 0.3 mg/L,具有愈伤组织生长速度快并易于分化;不定芽分化激素组合为6-BA 0.5 mg/L NAA 0.1 mg/L,继代培养组合6-BA 0.1 mg/L NAA 0.5 mg/L B90.3mg/L,增殖在8倍以上;生根培养组合1/2MS NAA0.6 mg/L,一般20 d左右生根,平均根量4～5条,生根率达92%.     

Induction of antiviral resistance and stimulary effect by oligochitosan in tobacco

Oligochitosan was applied by spraying it on tobacco leaves for inhibition of tobacco mosaic virus (TMV). The maximum inhibition of TMV by oligochitosan was observed when inoculation occurred at 24 h after spraying 50 μg ml⁻¹ oligochitosan. The production of H₂O₂ and NO in epidermal tobacco cells induced by oligochitosan was investigated by epidermal strip bioassay and LSCM, using cell permeable fluorophore diaminofluorescein diacetate (DAF-2D) and 2′,7′-dichlorofluorescin diacetate (H₂DCF-DA), respectively. Epidermal tobacco cells treated with oligochitosan resulted in a strong increase of intracellular NO and H₂O₂. Oligochitosan and NO donor sodium nitroprusside (SNP) induced the defense reaction against tobacco mosaic virus (TMV), and increased phenylalanine ammonia-lyase (PAL) activity. Co-treatment of the tobacco cells with oligochitosan and NO scavenger CPTIO blocked the inducing resistance. The results indicated that the defense response induced by oligochitosan was connected with NO pathway.     

滩羊尿对典型草原三种草地植物生长的短期作用特性

研究了不同尿液浓度和土壤含水量下，羊尿对典型草原植物茵陈蒿、委陵菜和狗尾草生长的短期作用特性。结果表明，不同施尿量施尿后1个月，狗尾草对羊尿沉积的响应为高尿液浓度负效应，低尿液浓度正效应；茵陈蒿和委陵菜为负效应。土壤含水量越高，羊尿对其分蘖（枝）的负效应越低。不同尿液浓度下，三种植物对羊尿响应的负效应顺序为茵陈蒿〉委陵菜〉狗尾草；且其分蘖（枝）对羊尿和土壤水分互作反应的正效应顺序为狗尾草〉委陵菜〉茵陈蒿。具体放牧过程中，可通过家畜适时饮水降低尿液浓度，以降低畜尿对草地的负效应。     

多年生黑麦草高频再生体系的建立及优化

从外植体预处理方式、基本培养基、激素浓度等方面着手,对多年生黑麦草愈伤组织诱导、继代、不定芽分化及再生过程中的影响因素进行了研究,提高了再生频率。结果如下：切取胚端半粒种子,经75%乙醇处理1min,0.1%HgCl处理15min,在经无菌水清洗4～6次后接种方式较好;愈伤组织诱导培养基以MS＋2,4—D 8.0 mg/L（或另添加甘露醇25 g/L）为佳;愈伤组织接种于MS＋2,4—D 8.0mg/L＋甘露醇25 g/L上进行1～2次继代后于NB＋6—BA2.0 mg/L上进行分化;不定芽转接至MS＋6—BA2.0 mg/L上进行扩繁或于1/2MS＋NAA0.5mg/L＋IAA0.5mg/L上进行生根。     

放牧强度、植被结构与草地生态环境的关系

本文综述了放牧对草地植物组成及植物生物量的影响、不同放牧方式和强度对家畜和草地的影响、高寒草甸地区人工草地建植和利用的研究进展。为了保护草地植物多样性及获得较高草地生产量,应使草地承受适当的放牧压力。     

羊草与灰色赖草杂种F1再生体系的建立

对羊草(Leymus chinensis)与灰色赖草(Leymus cinereus)杂种F1幼穗进行离体培养,建立了杂种F1植株再生体系.结果表明:不含任何激素的MS培养基是最佳的分化培养基,分化成苗率为66%;2,4-D对愈伤组织的诱导及其质地的改造有重要作用;3.0 mg/L 2,4-D MS培养基愈伤组织诱导率最高,为68%;2.0 mg/L 2、4-D MS诱导的愈伤组织胚性最强;诱导率与分化率没有直线对应关系;再生体系的建立为杂种F1育性恢复的研究奠定了基础.     

Effect of indole-acetic acid (IAA) on the development of symptoms caused by <Emphasis Type="Italic">Pythium ultimum</Emphasis> on tomato plants

The effect of indole-acetic acid (IAA) on the development of symptoms caused by Pythium ultimum on tomato plants was investigated using different bioassays. Application of IAA (5 μg ml⁻¹) on tomato seedlings inoculated with P. ultimum did not affect their emergence suggesting that IAA did not affect the severity of Pythium damping-off. However, IAA was shown to influence the development of P. ultimum symptoms on tomato plantlets. Low concentrations of IAA (0–0.1 μg ml⁻¹) within the rhizosphere of plantlets increased the severity of the symptoms caused by P. ultimum, while higher concentrations (10 μg ml⁻¹), applied either by drenching to the growing medium or by spraying on the shoot, reduced the symptoms caused by this pathogen. In addition, the study demonstrated that P. ultimum produces IAA in liquid culture amended with L-tryptophan, tryptamine or tryptophol (200 μg ml⁻¹) and in unamended culture.