Developmental study on the inflorescence and flower of Caldesia grandis Samuel (Alismataceae)

The inflorescence and floral development of Caldesia grandis Samuel is reported for the first time in this paper. The basic units of the large cymo‐thyrsus inflorescence are short panicles that are arranged in a pseudowhorl. Each panicle gives rise spirally to three bract primordia also arranged in a pseudowhorl. The branch primordia arise at the axils of the bracts. Each panicle produces spirally three bract primordia with triradiate symmetry (or in a pseudowhorl) and three floral primordia in the axils of the bract primordia. The apex of the panicle becomes a terminal floral primordium after the initiations of lateral bract primordia and floral primordia. Three sepal primordia are initiated approximately in a single whorl from the floral primordium. Three petal primordia are initiated alternate to the sepal primordia, but their subsequent development is much delayed. The first six stamen primordia are initiated as three pairs in a single whorl and each pair appears to be antipetalous as in other genera of the Alismataceae. The stamen primordia of the second whorl are initiated trimerously and opposite to the petals. Usually, 9–12 stamens are initiated in a flower. There is successive transition between the initiation of stamen and carpel primordia. The six first‐initiated carpel primordia rise simultaneously in a whorl and alternate with the trimerous stamens, but the succeeding ones are initiated in irregular spirals, and there are 15–21 carpels developed in a flower. Petals begin to enlarge and expand when anthers of stamens have differentiated microsporangia. Such features do not occur in C. parnassifolia. In the latter, six stamen primordia are initiated in two whorls of three, carpel primordia are initiated in 1–3 whorls, and there is no delay in the development of petals. C. grandis is thus considered more primitive and C. parnassifolia more derived. C. grandis shares more similarities in features of floral development with Alsma, Echinodorus, Luronium and Sagittaria. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140 , 39–47.     

马桑绣球(绣球科)的花器官发生和发育

在扫描电镜下观察了马桑绣球Hydrangea aspera孕性花的发生及发育过程。马桑绣球的花器官向心轮状发生：花萼原基以2/5螺旋式相继发生,花瓣原基几乎同步发生。花瓣开始发育时,与花萼相对的雄蕊发生。与花瓣相对的雄蕊原基与心皮原基几乎同时出现。初始心皮向上扩展,分化出花柱和柱头,向下延伸,嵌入花托,发育为下位子房。花发育成熟时,隔膜于子房的下部连续,而中部和上部不连续,即子房为不完全2室。经过与绣球属已观察过的另外5种1亚种花器官发生和发育比较,发现马桑绣球与藤绣球H. ano mala subs     

香菇半亲和双单杂交研究初报

选用一栽培株苏香两种孢子单核体自交后代作双核体亲本,与相应的孢子单核体进行半亲和双单杂交,得到6个杂交后代,均具有结实能力,说明半亲和双单杂交后代可以用于育种研究。大多数杂交菌株(核基因相同)在菌丝生长速率与CMC酶活方面显示出不同程度遗传差异,其中3号与4号菌株在菌丝生长速率与CMC酶活方面呈现明显杂种优势。     

Accumulation of 14C from exogenous labelled auxin in lateral root primordia of intact pea seedlings (Pisum sativum L.)

When [¹⁴C]indol-3yl-acetic acid was applied to the apical bud of 5-day old dwarf pea seedlings which possessed unbranched primary roots, a small amount of ¹⁴C was transported into the root system at a velocity of 11–14 mm h^-1. Most of the ¹⁴C which entered the primary root accumulated in the young lateral root primordia, including the smallest detectable (20–30 mm from the primary root tip). In older (8-d old) seedlings in which the primary root bore well-developed lateral roots, ¹⁴C also accumulated in the tertiary root primordia. In contrast, little ¹⁴C was detected in the apical region of the primary root or, in older plants, in the apices of the lateral roots.Abbreviations IAA indol-3yl-acetic acid     

Bud and crown architecture of white spruce and black spruce

Needle primordia in buds and branch lengths were assessed in the crown of a plantation-grown white spruce tree. There was a gradation in needle primordia in buds in branches within the crown. The largest number of primordia was in the terminal bud of the leading main stem shoot, with the number in first-order whorl lateral shoot terminal buds decreasing from whorl 1 to whorl 4, below which buds contained a similar small number of primordia (about one-third as many as in the terminal shoot). Previous year's shoot elongation followed a similar pattern (i.e., elongation of whorl branches was greater closer to the top of the tree and elongation in the fourth through ninth whorls was about one-third that of the main stem leader). Higher order branches within whorls had within-branch gradation in shoot elongation and number of needle primordia, with older branches having as few as 16–30 primordia in buds and 3–4 cm elongation for high-order branches on older main stem whorls. There were strong correlations between the number of primordia in branch terminal buds and branch length/diameter and bud length/diameter/volume. In both black spruce and white spruce, there were strong correlations of number of needle primordia in main stem leader terminal buds with number of needle primordia in terminal buds of first and second whorl leaders.     

Floral development in Astragalus caspicus Bieb. (Leguminosae: Papilionoideae: Galegeae)

Floral organogenesis and development of the bushy perennial legume Astragalus caspicus were studied using epi-illumination light microscopy techniques. Based on our observations, flowers are in axillary two-flowered racemes, initiate all 21 floral organs and show precocious appearance of zygomorphy. The order of floral organ initiation is unidirectional in whorls starting from the abaxial position of the flower with a high degree of overlap. Another important ontogenetic feature is the existence of two successive common primordial stages categorized as primary and secondary. The primary common primordia produce antesepalous stamens and secondary common primordia. In contrast, the five secondary common primordia subdivide into a petal and an antepetalous stamen primordia. Our findings on floral ontogeny of A. caspicus provide new evidence for the complex and variable floral initiation and development in legumes. The floral apex with strong overlapping initiation of different organs illustrates a paradox in which different capabilities must be presumed to exist simultaneously. Moreover, two extraordinary types of common primordia represent possibly an advanced evolutionary trend where time intervals between the initiations of different floral organs in Papilionoideae are shortened.     

Hymenial surfaces in developing agaric primordia

The early stages of primordial development are described for five boletes, six species of Russulaceae, two of Lentinellaceae and a single species of Hohenbuehelia (Tricholomataceae). The taxonomic significance of the observations is discussed.