七指蕨科和瓶尔小草科植物的叶表皮特征

在光学显微镜和扫描电子显微镜下,对七指蕨科和瓶尔小草科３个属３种代表植物的叶表皮内外面进行了观察。它们的表皮细胞形状较规则,垂周壁平直或略有弯曲,气孔器长轴与叶片长轴平行或近平行,保卫细胞下陷;但三属叶表皮在表皮细胞形状,     

器官间关系对叶片衰老的影响

叶片衰老是整个植株生理特性的敏感表现,受根系、茎、生殖器官和其他叶片等器官的影响。器官间关系影响叶片衰老可能是通过竞争体内营养、水分等物质、竞争环境因子、源库关系、激素等信息系统调节等机制实现的。从整株水平上加强叶片衰老的生理机制和控制技术研究,将为生产上控制衰老、减少叶片异常衰老造成的产量和品质损失提供有效的技术途径。     

菲氏叶猴与黑叶猴的下颌骨

本文对15只菲氏叶猴和8只黑叶猴成年下颌骨作了功能形态学研究。在21项所分析的变量中,两种之间有4项达到显著性差异水平,而10项达到非常显著的差异水平。从所分析的结构看来,菲氏时猴下臼齿及门齿的面积大于黑叶猴,而黑叶猴的咬肌附着部分(支高、颌高,支宽及髁头长)大于菲氏叶猴。这表现了黑叶猴比菲氏叶猴具更强的咀嚼能力。因而,可以推测在食物成分中,黑叶猴食坚果的比例要大于菲氏叶猴。     

THE LEAF OF CALYCADENIA AND ITS GLANDULAR APPENDAGES

Carlquist , Sherwin . (Rancho Santa Ana Botanic Garden, Claremont, Calif.) The leaf of Calycadenia and its glandular appendages. Amer. Jour. Bot. 46(2) : 70-80. Illus. 1959.—Large tack-shaped glands are characteristic of the leaves of Calycadenia which are associated with the inflorescence. These glands may be divided into those which are terminal on leaves and those which occur laterally on the surface of the leaf. Lateral glands show stages early in their development which are identical with those of simpler trichomes of Madinae. Terminal glands, which possess more vascularization of the stalk, show a more modified form of development. Vascularization is not derived from protoderm, but from more deeply-seated cells. These cells are included in a zone of elongation which forms the stalk. Vascular bundles may extend to the base of glands which lack vascularization in their stalks. Tack-shaped glands are considered an advanced form of trichome in which internal tissues of the leaf are involved. Within the genus Calycadenia, ontogenetic and comparative studies suggest that the following characters are advanced: reduction to a single terminal gland, “inrolling” of margins to form a cylinder of bundles, concomitant with a central core of fibers or a pectic channel. Systematic distribution of gland occurrence and of types of foliar structure are given.     

MORPHOLOGY AND DICHOTOMOUS VASCULATURE OF THE LEAF OF KINGDONIA UNIFLORA

Foster , Adriance S. (U. California, Berkeley), and Howard J. Arnott . Morphology and dichotomous vasculature of the leaf of Kingdonia uniflora. Amer. Jour. Bot. 47 (8): 684–698. Illus. 1960.—An intensive study of the nodal anatomy, petiolar vasculature and open dichotomous venation of the leaf of Kingdonia has revealed a type of foliar vascular system of unusual morphological and phylogenetic interest. The vascular supply at the nodal level consists of 4 collateral traces which diverge from a single gap into the sheathing leaf base. This type of nodal anatomy is perhaps primitive, and comparisons are made with the unilacunar nodes and the 2- and 4-parted leaf trace systems characteristic of many angiospermous cotyledons and the foliage leaves of certain woody ranalian genera. The petiole of Kingdonia is vascularized by 2 pairs of bundles which represent the upward continuation of the 4 leaf traces. A transition from an even (4) to an odd (3) number of strands occurs near the point of attachment of the 5, lobed, cuneiform lamina segments to the petiole. Each of the 2 abaxial bundles dichotomizes and the central derivative branches fuse to form a double bundle which enters the base of the median lamina segment. The 2 adaxial petiolar bundles diverge right and left into the bases of the paired lateral segments of the lamina. An analogous type of transition from an even to an odd number of veins occurs in many angiospermous cotyledons which develop a definable mid-vein. But, in Kingdonia, the bundles which enter the bases of the lamina segments give rise to systems of dichotomizing veinlets devoid of “mid-veins.” Although the majority of the terminal veinlets enter the marginal teeth of the lamina segments, “blind” endings, unrelated to the dentations, occur in all the leaves studied. Typically, all of the vein endings in a given lobule of a lamina segment are derived from the same dichotomous vein system. However, in some leaves, a veinlet dichotomizes directly below a sinus and the branches diverge into the marginal regions of 2 separate lobules. The phylogenetic significance of the occurrence of open dichotomous venation in such an herbaceous angiosperm as Kingdonia is briefly discussed. From a purely morphological viewpoint, the Kingdonia type of venation invites direct comparison with the venation of Sphenophyllum, certain ferns or Ginkgo rather than with any of the known reticulate venation patterns of modern angiosperms. Although the foliar venation of Kingdonia may represent the result of evolutionary reversion, the very rare anastomoses which occur seem primitive in type rather than “vestiges” of a former system of closed venation.     

淹涝胁迫对水稻叶鞘和叶片中淀粉粒分布的影响

淹涝是世界上当前所面临的最严重自然灾害之一,尤其是近几年来,淹涝给我国的农业生产带来了巨大损失,全国平均每年受涝面积814万hm2,其中成灾面积448万hm2,损失粮食约28亿kg〔1〕。水稻是我国的主要粮食作物,并且分布于淹涝易发生的南方多雨潮湿地区和北方低洼地带,淹涝对水稻产量影响极大,因此,研究淹涝胁迫对水稻的伤害及水稻的耐淹机制越来越受到人们的重视〔2〕。淹涝对植物的伤害并非是因为水分过多而造成的直接伤害,而是由于淹涝造成的次生胁迫,其中最严重的是缺氧。在缺氧条件下,细胞中的碳水化合物代谢途径改变,对植物的生长和发育…     

THE ROLE OF LIGHT IN HISTOGENESIS AND DIFFERENTIATION IN THE SHOOT OF PISUM SATIVUM. II. THE LEAF

Thomson , Betty F., and Pauline Monz Miller . (Connecticut Coll., New London.) The role of light in histogenesis and differentiation in the shoot of Pisum sativum, II. The leaf. Amer. Jour. Bot. 49(4): 383–387. Illus. 1962.—Development of the form and anatomy of leaves was studied in plants of Pisum sativum grown in vermiculite under constant conditions and exposed daily to red or white light or kept in continuous darkness. The red light used had an intensity in the morphogenetically active red region of the spectrum of 70–75% that of the white light. Light had no effect on the manner of initiation or early development of leaf primordia. Quantitative data from older leaves showed that light has no effect on the pattern of later development but does affect the rate and extent of development. Under all light conditions, the length of the leaflet is closely correlated with the state of its internal anatomy. “Mature” etiolated leaves duplicate young stages of light-grown leaves. Mature leaves grown in red light duplicate not-quite-mature leaves grown in white light. The difference between white-light and red-light leaves is attributed here to light intensity and resembles that between sun and shade leaves.