Effect on the Progeny of Applying Different Day Length and Hormone Treatments to Parent Plants of Lactuca scariola

Seedlings of the self-fertilizing species Lactuca scariola L. grown continuously in 8 h days did not flower even one year from sowing. Seedlings grown in 16 h days uatil flower buds appeared 96 days after germination were either transferred to 8 h days or treated weekly with gibberellic acid (GA₃), abscisic acid (ABA) or chlormequat (CCC) and retained, together with untreated control plants, in 16 h days. Each growth regulator caused characteristic morphological changes in the treated plants. All these plants flowered and produced seeds but the seeds showed distinct differences in weight, in their time to germination and in the seedlings which they produced. Germination and seedling characters depended on the light regime during germination as well as on the chemical applied to the parent plant and the rate of application. The parental treatment also affected the shape and size of the seedlings on a given day after germination, and certain treatments of the parent plant (transfer from long to short days and treatment with CCC in long days) advanced the flowering date of the seedlings. The gibberellin level in the seeds was raised, in increasing order, by treatment of the parent plant with 100 mg/1 GA₃, transfer from long to short days, 10 mg/1 GA₃, and 5000 mg/l CCC. It is suggested that the effect of day length on plant performance is mediated by the level of growth regelating substances within the plant and that the behaviour of seeds can be modified by the parental environment via the accumulation of different levels of certain growth factors in the seeds. A rise of one growth substance in the parent plant can result in the accumulation of a different one in the seeds.     

Dry storage temperatures, duration, and salt concentrations affect germination of local and edaphic ecotypes of Hordeum spontaneum (Poaceae) from Israel

Hordeum spontaneum , the ancestor of cultivated barley, is mainly distributed in the Mediterranean zone of the Near East as well as in the Irano-Turanian steppes and Saharo-Arabian region; these areas receive unpredictable small amounts and distribution of rain followed by long, hot and dry summers. Caryopses of seven local ecotypes of H. spontaneum were collected in Israel from natural populations near Sede Boker, Neve Yaar, Tabigha and Mount Hermon. Three generations of these ecotypes were grown in natural conditions at Sede Boker with additional irrigation. The germination of caryopses of the third generation was tested. Due to the self pollination and atelechoric system of seed dispersal of this species, genetic ecophysiological diversity of afterripening and salt tolerance was found between the ecotypes originating from different areas, even within local populations and patches of plants that grew on different types or depths of soil at a distance of only a few meters from each other. Afterripening is important to prevent the caryopses from germinating shortly after maturation after a late rain at the beginning of the dry summer. Germination of the different ecotypes is regulated by temperature and length of post-maturation dry storage, as well as temperatures during wetting, and salinity.     

9种芦荟属植物叶的结构和芦荟素含量的比较研究

9种芦荟属植物叶的比较解剖研究结果表明,它们都具有明显的旱生叶的结构特征,其维管束的韧皮部内都有大型薄壁细胞,但其表皮角质膜的厚度,表面纹饰,气孔上,下腔的形状和大小,同化组织 导 ,细胞分化情况,维管束的大小,分布密度和其大型薄壁细胞占维管束的比例,中央贮水组织占叶横切面的比例等特征,在各种间存在差异,且性状稳定,可以作为该属内种间分类的解剖学指标,植物化学分析结果表明,9种植物叶内蒽醌类物质的主要种类和含量不同,其含量高,低与叶内维管束密度,大型薄壁细胞占维管束的比例以及同化组织的厚度密度切相关,从而为芦荟属植物选育商业用良种提供了植物解剖学依据。     

野生二棱大麦种子休眠型态与农艺性状及生态地理因素相关性研究

对来自以色列不同地区16个生态型野生二棱大麦种子的休眠型态与其农艺性状及起源地生态地里因素的相关性进行了研究。结果表明：高温（40℃）储藏可以打破种子的休眠;16个生态型种子在高温处理下的萌发率表现出显著差异,其休眠打破过程显示出不同型态的对数生长曲线：8个旱生生态型为S型,而8个湿生生态型为倒L型。休眠深度用实际达到最大萌发率的时间度量,最低休眠深度（15·6d）是来自湿润地区＂进化峡谷＂的生态型37-N,而最深休眠深度（103·1d）是来自干旱地区Ein-Zukim（死海附近）的生态型32-6。此外,对11个物候及农艺性状指标与休眠深度做斯皮尔曼秩相关分析,结果有9个显示出显著相关,尤其是粒重与休眠深度有极显著相关性。同时,休眠深度与起源地15个生态地理因素中的9个有显著相关,种子休眠主要受其起源地的地理位置、温度和水分条件等影响。可见,野生二棱大麦自然选择进化了休眠特性去应对干热环境而繁衍生息。本研究结果可用于进一步遗传研究和现代栽培大麦品种的改良。     

芦荟属3种植物不同叶龄、不同部位叶内蒽醌类物质含量及其变化的研究

用植物化学技术研究了3种芦荟属植物不同叶龄和不同部位叶中蒽醌类物质的含量及其变化。结果表明,被研究的芦荟属3种植物叶中主含的蒽醌类物质有：芦荟素或高那特芦荟素,芦荟宁和芦荟苦素。其中,中华芦荟和木立芦荟主含芦荟素;海莱芦荟主含高那特芦荟素。叶各部位详细分析的结果表明,蒽醌类物质在植株上部的嫩叶中的含量要高于下部老叶;同一叶中,叶尖高于叶中部,叶基含量最低;而叶缘含量高于叶的中央部分。在同一叶的横切面上,蒽醌类物质的含量在维管柬区最高,同化薄壁组织部分次之,储水组织部分最低。芦荟属植物在同一个植物体不同的叶之间,以及同一叶不同的位置间有规律的累积蒽醌类物质有重要的生物学意义。它是保证芦荟属植物在原产地的干旱和半干旱生活环境中得以良好生存的适应反应和化学防御机制。     

中华芦荟叶的解剖学、组织化学和植物化学研究

用解剖学,组织化学和植物化学方法研究了中华芦荟（Aloe vera L.var.chinensis(Haw.)Berg.)叶的结构,芦荟素的含量及其可能的储藏和合成场所,解剖学研究结果表明,中华芦荟叶的结构由表皮,同化薄壁组织,维管束和储水组织组成,其旱生结构特征比较明显,表皮具厚的角质层,外切向壁次生加厚,气孔下陷,中央储水组织发达,绿色组织没有明显的分化,其中,5个细胞环绕的气孔器和叶基出现的第二轮维管束在芦荟属中首次报道,具有种的特征,中华芦荟叶中所含的蒽醌类次生代谢物主要是芦荟素（barbaloin or aloin),其含量和叶位及同一叶的不同部位有关,植株上剖嫩叶及每一叶的上部含量高于下部老叶和叶的中部,叶基部含量最低,比较被测的解剖学指标和植物化学分析的结果发现,叶中维管束的密度和芦荟素的含量呈明显的正相关,用5％Pb(CH3COOH)2沉淀处理及5％NaOHR颜色反应检测芦荟素的储藏物合成部位,初步结果表明,位于韧皮部端的数个发达大型薄壁细胞是芦荟素的储藏场所,而绿色组织和维管束鞘是可能的合成场所。     

土壤盐分、预湿处理对Artemisia monosperma(菊科)种子传播和萌发的影响

Artemisia monosperma是分布于西奈半岛以及以色列地中海沿岸许多活动沙丘及固定沙丘上的建群种植物,在固定沙丘上,雨后的蓝细菌结皮上能产生径流水,A.monosperma的种子在径流水上漂浮并被传播到低洼处或土壤缝隙中,实验表明,有一半的种子在蒸馏水上漂浮3d,而在各种浓度的盐溶液上则能漂浮更长时间,低浓度的盐溶液对种子的萌发无影响而高浓度的盐分抑制种子的萌发,NO3^-可能是影响种子在沙质蓝细菌结皮上萌发的因素,低浓度的NO2＿促进种子萌发而高浓度则抑制。预湿处理的实验表明,在自然生境中,暴露地表或埋在浅表层的种子经受每晚的露水以及小量雨水的反复湿,春萌发力有可能通过强人作用而提高。     

光照、温度和盐分对梭梭种子萌发的影响

梭梭是我国西北荒漠中分布的多年生植物,属中亚荒漠植被成分。其种子萌发的最适温度为10℃,亚适宜温度为15～20℃。从20℃起,温度越高,萌发比率越低。种子无论在光下和暗中都能萌发,萌发率无显著性差异。浓度低于0.2mol/L的NaCl溶液对萌发的影响不大;但从0.8mol/L起,萌发率随着浓度增高而降低,直至为零。将在盐溶液中处理9d的种子转移至蒸馏水后,原来较高浓度下的种子具有较高的萌发恢复率。不同浓度下的种子的萌发率和萌发恢复率要比蒸馏水中的低,表明NaCl处理后的部分种子永久地失去萌发力。     

Anatomy,Histochemistry and Phytochemistry of Leaves inAloe vera var. chinensis

A multidisciplinary approach—anatomy, histochemistry and phytochemistry—was used to investigate the leaf structure, the content and the storage location of barbaloin in the leaves of Aloe vera L. var. chinensis (Haw.) Berg. Xeromorphic characteristics including secondary thickened epidermal cell walls, thicker cuticle, ambiguous differentiation of spongy and palisade tissues in the chlorenchyma, and well-developed aquiferous tissue could be seen in the leaves. Several large parenchymatous cells were observed at the phloem pole of the first ring of vascular bundles. The secondary ring of vascular bundles in the leaf base and the stomata, which are surrounded by five cells, have some classification significance in this species. The density of vascular bundles, the content of barbaloin and the intensity of histochemical reaction differed among leaf numbers L1 (annual leaf), L2 (biennial leaf), L3 (triennial leaf) and L4 (quadrennial leaf), and in different parts of the leaf. These three factors were highest in the youngest leaf, L1, and top parts of all the leaves and lowest in the basal parts and the oldest leaf, L4. The density of vascular bundles had a positive correlation to the content of barbaloin. The histochemical results revealed that the small sheath cells that surrounded the bundles might be the location of barbaloin synthesis and the large parenchymatous cells beneath the sheath might be the storage places of this metabolite.     

Comparison of Germination Strategies of Artemisia ordosica with Its Two Congeners from Deserts of China and Israel

Artemisia ordosica Krasch. is a dominant shrub occurring mainly on stable sand dunes in the Gobi Desert of China, in the Mongolian phytogeographic region. Achenes of A. ordosica germinate in light but poorly in dark and light is the limiting factor regulating the achene germination in sand depth. Achenes germinate in spring or autumn with an optimal temperature of 20 ℃. Achene mucilage can absorb large amounts of water and has important ecological function. Salt concentrations and sand moisture may regulate achene germination in sand. A. ordosica, A. sphaerocephala Krasch. and A. monosperma Delile. from different climates have similar responses to light, the underground location of achene, and sand moisture. Percentage of seedling emergence from different levels of sand depth is depends on the specific, temperature and intensity of light penetrating through the sand depths, as well as on sand moisture. The desert sand habitat seems to have had a dominant influence on the evolution of the germination strategies of these 3 Artemisia species.