Journal of University of Chinese Academy of Sciences

An Embryological Investigation and Systematic Position of Cephalotaxus oliveri Mast.

Li Ying, Wang Fu-Hsiung, Chen Zu-Keng

1986, 24 (6): 411-422.

Abstract ( 0 )

The tapetum is of the secretory type. After breakdown of callose wall around

tetrads, tapetal cells degenerate quickly and disappear completely at the late stage of micros-

pore development. The mature male gametophyte is of a tube cell and a generative cell, with-

out prothallial cells. The pollen tube lodging in the nucellus contains a spermatogenous cell, a

tube nucleus and a sterile cell before entering domancy. In the following spring the pollen

tube grows fast, and reachs the female gametophyte when the archegonia are mature. The sper-

matogenous cell enlarges obviously, and the cytoplasm is very dense in the centre of the cell

and shows well-marked radiations from this region to the periphery, when it divides to form

two sperm cells of unequal size, while the tube nucleus and the sterile cell degenerates and sub-

sequently disappears. After 12th simultaneous divisions the cell wall of the female gametophyte

forms from the periphery to the centre. When the central cell has divided to form the egg and

the ventral canal nucleus ,its cytoplasm becomes very dense and numerous bodies, similar to nu-

cleoli in appearance, occurs. The sperm and the egg come together at metaphase of the first

division of the zygote. The wall formation of proembryo initiates at the 16-nucleate stage.

The features of the mature embryo are as follows: (a) The cotyledons are very long, with

their length about four fifths of that of the whole embryo, (b) the embryonal axis is so short

as to cover only about one sixth of the cotyledons, (c) there is no typical pith, (d) the root cap

is well-developed and consists of about 10-15 layers of cells which are very large and are full

of starch grains and (e) the epidermis cells only extend to the upper part of the root cap. It

is concluded that Fu's (1984) suggestion, that the Cephalotaxus be divided into two sections, Ce-

phalotaxus and Pectinatae, is supported by the present embryological investigation on C. oliveri.

Comparative Anatomy of the Secondary Phloem of the Stem in Cephalotaxus

Hu Yu-Shi, Shao Wei

1986, 24 (6): 423-427.

Abstract ( 0 )

The family Cephalotaxaceae contains only one genus, Cephalotaxus, with 9 spe-

cies and some varieties, mostly endemic to China.

The present paper deals with the comparative anatomy of secondary phloem of stems in 4

species and I cultivar, of this genus under light microscope and scanning electron microscope.

The main results are as follows:

(1) The structure of secondary phloem is rather uniform in the various species of this

genus. In cross section, sieve cells, phloem parenchyma cells form continuous tangential rows

of one cell in width respectively, which occur alternately. Sclerenchyma cells also form con-

tinuous tangential rows, each with a radial width of 1-4 cells. The interval between the rows

is rather wide.

(2) The type of phloem fiber and the quantity of sclereids can be served as the chara-

cters for identification of species and the evidence for the separation of two sections of Cepha-

lotaxus, namely: Cephalotaxus and Pectinatae.

(3) The secondary phloem of this genus contains more or less crystalliferous parenchyma

cells, in the inner tangential walls of which calcium oxalate crystals are embedded. So far this

character has not been reported in the other families and the genera of conifers. Our conclu-

sion, therefore, agrees with the opinion that Cephalotaxaceae is a natural taxon and includes

only one genus, Cephalotaxus.

A Comparative Study on Function and Membrane Proteins of Chloroplasts of Three Species of Cephalotaxus in Late Winter

Ma Hong, Zhang Zheng-Dong, Li Liang-Bi, Ma Gui-Zhi, Zhai Xiao-Jing, Zhou Pei-Zhen

1986, 24 (6): 428-433.

Abstract ( 0 )

Three species of evergreen Cephalotaxus (C. fortunei Hook. f., C. sinensis Li and

C. harringtonia cv. Fastigiata) were used as materials to study some functional properties of

chloroplasts. It is found that the oxygenevolving capacity of the chloroplasts from these plants

is inhibited but partial reaction of PS-II and effect of Mg²⁺ on energy distribution between

two photosystems are detectable during the winter. Seasonal effects on the functional properties

of chloroplasts from evergreen Cephalotaxus are similar to that of conifer chloroplasts.

The ratio between F₆₈₅, F₆₉₅ and F₇₃₅ of fluorescence emission spectra at 77°K of ch-

loroplasts is different among these three species. It is found by using SDS-PAGE that the num-

ber of polypeptide resolved from thylakoid membrane of C. harringtonia cv. Fastigiata sub-

stantially differs from that of C. fortunei Hook.f. and C. sinensis Li. The result shows that the

fluorescence emission spectrum feature and polypeptide composition of thylakoid membrane may

be used as a tool for systematics of the genus Cephalotaxus.

Studies on Pollen Morphology of Podocarpaceae from China

Xi Yi-Zhen

1986, 24 (6): 434-438.

Abstract ( 0 )

The pollen morphology and ultrastructure of exine of Podocarpaceae in China

were examined with light microscope, scanning electron microscope and transmission electron

microscope. The pollen grains of Podocarpus have rather large and prominent sacs on both

sides of body, and are 53.9-74.8 μm long in total, with their bodies 29.6-45.2 μm long and

19.1-31.3 μm wide. The sacs are smooth on outer surface with perforation, but reticulate insi-

de. On distal view, they are obviously of radial muri from its base. The body is oblate or

spheroidal, laddershaped on distal face. The exine of the capis tuberculate, but more distinct-

ly on the margin than in the centre. The pollen grains of Dacrydium are of small and indis-

tinct sacs around body, which are composed of many small bladders. The body is subcircular

in outline. Both body and sacs are irrugulate tuberculate under SEM. Examination of thin

sections of Podocarpus macrophyllus var. maki with TEM reveals that the exine includes ecte-

xine and endexine. It is interesting to note that foot layer of ectexine possesses lamellar stru

cture, but endexine is homogeneous in structure and lighter in colour. This character is speci-

fic in the gymnosperms. Based on informations of fossil pollen grains, Podocarpaceae is rather primitive and of ancient origin.

Ultrastructure of Pollen Exine in Amentotaxus Pilger and Its Significance in Taxonomy

Xi Yi-Zhen

1986, 24 (6): 439-442.

Abstract ( 0 )

Amentotaxus consists of three species distributed in southern, central, western

mainland and southern Taiwan of China. Its pollen grains were examined by LM, SEM and

TEM. The pollen grains of this genus are suhsphaeroidal, sometimes suboblate or irregular,

27.8 μm to 45.4 μm in diameter, at tenuate towards distal pole. It is worthy of note that a num-

ber of pollen grains in Amentotaxus argotaenia possess relic saccuses. The exine surface con-

rains tuberculate ornamentation of two sizes, i,e. sparse and coarse tuberculae and rather dense

and fine tuberculae under SEM. TEM examination reveals that endexine is of lamellate structu-

re containing 7-9 lamellae. Ectexine is composed of tectum, granulate layer and food layer.

Tectum is very irrigular, consisting of tuberculae which are linked up forming strings of beads

or fused into a number of masses. The granulae of granular layer under the tectum are distri-

buted in heaps. These granulae are easily fallen in some cases. The foot layer is made of 1-

2 thick and dark lamellae which are as dark as the tectum and possess tripartite structure, i,e.

with a central white line and coarse and dark lines on both lateral sides. But lamellae of en-

dexine are thin and light and have no tripartite structure. Ultrastructure of pollen exine of

Amentotaxus is obviously distinguished from that of Taxaceae and Cephalotaxaceae. The chara-

cteristics of ultrastructure of pollen exine in Amentotaxus support its being seperated from Ta-

xaceae and treated as an independent family, Amentotaxaceae.

Study on Chemical Components in Leaves of Amentotaxus argotaenia (Hance) Pilger Native to China

Ma Zhong-Wu, He Guan-Fu, Yin Wan-Fen

1986, 24 (6): 443-446.

Abstract ( 0 )

Eight crystalline substances are isolated from leaves of Amentotaxus argotaenia na-

tive to China. Five of them are identified as known A-homo-5-cholest-6-en-3-One, cyclobala-

none, nonacosan-10-ol, r-sitosterol and β-sitosterol. The others seem to be new components,

whose structures will be studied further.

Investigation on Sexual Reproductive Cycle in Torreya grandis

Tang Zhong-Xun, Chen Zu-Keng, Wang Fu-Hsiung

1986, 24 (6): 447-453.

Abstract ( 0 )

Before May the first, the ovular primordium of Torreya grandis has differentiat-

ed. From this early moment the primordium look like the parabolic form and it is surrounded

by many pairs of scales, of which a pair of the inner scales are lying at the same level as the

primordium of ovule. About May the first of the second year, the differentiation of the various

tissues in the ovule has essentially completed. And the fertilization takes place from the end of

August to the beginning of September. After overwintering, the proembryo developes into a

young embryo in April of the third year, and at the last stage both the seed and the embryo beco-

me mature from September to November.

In the Taxaceae, the embryogenesis is similar in Amentotaxus,Austrotaxus, Taxus, and Pse-

udotaxus; their proembryos form cell wall all at the stage of 16-free nuclei and simple polyem-

bryony is common among them. In Torreya, however, the cell wall of proembryo appear at the

stage of 4 or 8-free nuclei, and cleavage polyembryony is its feature. On the basis of our obser-

vation, the sexual reproductive cycle of Torreya grandis seems to have two important features,

one of which is rather long (31 moths from ovular primordium to seed maturity; about 4 mon-

ths from pollination to fertilization and 7-8 months for development of proembryo). The sta-

te of the long sexual cycle in Amentotaxus and Austrotaxus is different from each other; in the

former development of young embryo lasts 10-11 months, and in the latter the interval between

pollination and fertilization is 13.5 months. The second feature of the sexual cycle in Torreya

grandis is over two winters: development of the sporogenous cells in the first, and the proembryo

development in the second. From the point of view of phylogenesis, some primitive characters

are present in the sexual cycle of Torreya grandis although a specialized feature of the embryoge-

nesis occurs in some degree.

Studies on Essential Oil Composition in Leaves of Torreya grandis cv. ‘Merrillii' and Chemotaxonomy

He Guan-Fu, Ma Zhong-Wu, Yin Wan-Fen, Xu Zhi-Ling, Pan Jiong-Guang, Zhu Qi-Cong

1986, 24 (6): 454-457.

Abstract ( 0 )

The chemical components of different genera and species of Taxaceac have been

analyzed in order to provide the data for discussion of the systematic position of this family. A

characteristic component kayaflavone from the leaves of Torreya grandis cv. ‘Merrillii' has been

reported in our previous paper. Recently we have obtained also a new diterpene torreyagranda-

te from the leaves of this species. The present paper deals with our preliminary study on essen-

tial oil composition of the leaves in the same species. 26 components have been identified. Three

of them, limonene, α-pinene and δ-3-carene, are the main ones, with their contents being 44.24%,

20.75% and 4% respectively. The essential oilalso contains torreyol which is a characteristic

component in this species.

Late Embryogeny of Pinus bungeana

Chen Zu-Keng, Wang Fu-Hsiung

1986, 24 (6): 458-463.

Abstract ( 0 )

Except for Pseudolarix, which is endemic to China, the late embryogeny of ten

genera of Pinaceae has been reported before in the diffferent degree. Among them the mature

embryos of Keteleeria evelyniana are different from those of the others in having well-developed

cotyledons and a very short hypocotyl. As far as information we have is concerned there are

three types in structure of the mature embryos of Pinaceae. The first type occurs in Keteleeria

and Cedrus, which have very well-developed cotyledons; the second one appears in Picea and

Larix, in which the hypocotyl and the root cap are equal in length; the third one, to which

Pinus bungeana belongs, includes all the other genera of Pinaceae. The last type is of a promi-

nent hypocotyl in the mature embryos. It is interesting to note that the mature embryos of Tor-

reya grandis and Keteleeria evelyniana are very similar in having specially developed cotyle-

dons, while the proportions of the various tissues in the mature embryo in Fokienia of Cupres-

saceae as well as Taxus and Amentotaxus of Taxaceae are similar to those of Pinus bungeana.

The pith and secretory cells are usually present in the mature embryos of Pinaceae. Although

no pith is present in those of Metasequoia and Taiwania of Taxodiaceae, the secretory cells ge-

nerally occur in their embryos in Fokienia of Cupressaceae and Taxus and Pseudotaxus of Ta-

xaceae, neither pith nor secretory cells are present in their hypocotyl. From above, the struc-

tures of mature embryos among Pinaceae, Taxodiaceae and Cupressaceae are different from one

another to some degree.

The most outstanding feature of the matur embryos in Pinus bungeana is that the shoot

apex is very well developed, with a high H/D ratio, about 0.83 on an average, even up to 0.96

in some case. Above-mentioned H/D ratio of Pinus bungeana is rare in the mature embryos of

conifers. Gifford (1943) reports that the average H/D ratio of shoot apex of Ephedra altissima

is from 0.44 to 0.68, while in 5-year-old branch apex of Pinus ponderosa, the average ratio is

about 0.25, and that in l5-year-old branch apex is about 0.35. For the apex of the dormant

short shoots of Pinus densiflora the average ratio is about 0.35, but that of shoot apex is about

0.52 when new buds have just formed. According to the present data about shoot apices of both

branches and mature embryos, the average ratio of shoot apex of mature embryos in Pinus bun-

geana is the largest one. From the present investigation the shoot apex of mature embryos of

Pinus bungeana exhibits four distinct tissue zones, i.e. the apical initials, the central mother cell

zone, the peripheral tissue zone and the rib meristem. It is worthy of note that the shoot apex

of Pinus strobus may be divided into five zones, including transition zone between central mother

cells and rib meristem (Owston, 1968). Four zones are recognized in the shoot apex of

Pinus lambertiana and P. ponderosa, without transition one (Sacher, 1954). From cytological

zonation, the shoot apex of mature embryos in Pinus bungeana is rather similar to that of Pinus

lambertiana and P. ponderosa.

SEM Observation of the Inner Surface Structure of Needle Cuticles in Pinus

Hu Yu-Shi

1986, 24 (6): 464-468.

Abstract ( 0 )

Comparative investigation on the inner surfaces of needle cuticle of Pinus was made

for 17 species and two varieties under SEM. It is shown that the differences in protrusions and

depressions of the internal cuticle surfaces of needles in the genus are not remarkable. Howe-

ver, the features of intercellular flanges are rather distinct and three types can be distinguished.

They are: (1) Subgen. Strobus (Sweet) Rehd (except Sect. Parrya) is of the Pinus koraiensis

type; (2) Subgen. Pinus is of the P. tabulaeformis type; (3) Sect. Parrya Mayr of Subgen. Stro-

bus (Sweet) Rehd is of the P. bungeana type. The character may provide taxonomy of the genus

Pinus with a new piece of evidence.

Based on the features mentioned above, together with many others, such as wood anatomy,

warts of wood tracheids, bark structure, needle anatomy and cuticle structure as well as ka-

ryotypic analysis in Pinus, the author considers that division of Pinus into two subgeuera is na-

tural and that separation of Sect. Parrya Mayr from Subgen. Strobus (Sweet) Rehd. and the

subsequent establishment of the subgenus Parrya of its own are also reasonable.

Male Gametophyte of Cathaya

Wang Fu-Hsiung, Chen Zu-Keng

1986, 24 (6): 469-470.

Abstract ( 0 )

There are two prothallial cells in Cathaya, but their formation is different from

that of the other genera of Pinaceae. A primary prothallial cell is cut off first and the division

of this cell gives rise to 2 prothallial cells which remain intact in mature pollen grains. 3-celled

pollen grains are formed. The interval between polination and fertilization is about 13 mon-

ths. The two sperms are different in size.

Biochemical Systematics of Gymnosperms (4)—Seed Protein Peptides and Needle Peroxidases of Taxodiaceae

Hu Zhi-Ang, Wang Hong-Xin, Liu Chang-Jiang

1986, 24 (6): 471-474.

Abstract ( 0 )

An analysis of seed protein peptides by using SDS polyacrylamide gel electropho-

resis, indicates that all members in Taxodiaxeae share three peptides with molecular weights of

24, 32 and 10 kilodaltons. Generally, seeds of this family contain 2 to 4 major peptides, and

their molecular weights are distributed in two regions: 24-26 K and 29-36 K respectively. The

quantity of these major peptides is near or even more than 50% of seed total protein content.

This kind of protein profiles is similar to that of Taxaceae and Cephalotaxaceae rather than to

that of Pinaceae. On the other hand, a considerable difference was observed in peptides with

higher molecular weights. Among different species within a genus, no difference has been found

both in their seed protein profiles and in their needle peroxidases. Based on the data cited here,

it seems that the relationships among most genera of Taxodiaceae are not so closed as the rela-

tionship among following genera: Sequoia, Sequoiadendron and Taxodium.

Isoperoxidases of Interspecific Hybrids in Pinus

Hu Zhi-Ang, Wang Hong-Xin

1986, 24 (6): 475-475.

Abstract ( 0 )

Postscript

Wang Fu-Hsiung

1986, 24 (6): 476-476.

Abstract ( 0 )

Additional Notes on Tarenna acutisepala How

Chen Wei-Chiu

1986, 24 (6): 477-478.

Abstract ( 0 )

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