The development of the placenta in the anthocerote Phaeoceros laevis (L.) Prosk

Gambardella, R.; Ligrone, Roberto

doi:10.1007/bf00393859

Cited by 15 publications

(10 citation statements)

References 15 publications

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“…At the sporophyte/gametopbyte junction in Phaeoceros (Gambardella, Ligrone & Castaido, 1981 ;Gambardella & Ligrone, 1987), Anthoceros (Chauhan & Schraudoif, 1986) and Folioceros (Vaughn & Hasegawa, unpubiished), the gametophyte transfer cells contain pleomorphic plastids with a reduced thyiakoid system and are generally devoid of starch (Fig. 10 A).…”

Section: Hi Varl'vtions In Ch Lo Ropl'^st (Plastid) Ultrastructurementioning

confidence: 99%

The anthocerote chloroplast: a review

Vaughn

Ligrone²,

Owen

et al. 1992

New Phytologist

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SUMMARY This review covers previous data, together with new information from our laboratories, on the subject of the anthocerote chloroplast. Unlike all other archegoniates, most species of anthocerote have pyrenoids in their chloroplasts. The pyrenoid is the site of accumulation of the first enzyme in the C3 photosynthetic cycle, ribulose bispbosphate carboxylase/oxygenase. Unlike most algae, the hornwort pyrenoid is composed of distinct subunits, numbering up to several hundred. Pyrenoid morphology is quite variable among the genera in shape, fine structure, and distribution of inclusions. Another unique feature of the anthocerote chloroplast is the presence of thylakoids that connect adjacent granal stacks at right angles to the long axis of the granum (so‐called channel thylakoids), resulting in a 'spongy’arrangement of the thylakoid system. The granal stacks of anthocerotes are like the‘pseudograna’of green algae because they lack the highly‐curved end membranes typical of all other embryophytes. The channel thylakoids are enriched in photosystem (PS) I and the grana are enriched in PS II. The chloroplast envelope is a double membrane structure with regions of appression, much like that of other green plants. The apieal cell of the gametophyte contains chloroplasts similar to the mature chloroplasts of the thallus, although certain gametophytic tissues may contain underdeveloped plastids. Chloroplasts in cells around Nostoc colonies and in cells invaded by mycorrhizal fungi have thylakoids mainly in pairs, and small or absent pyrenoids. A number of similarly reduced plastids are noted in the placental cells at the sporophyte/gametophyte junction and in developing spores. The greatest reduction is observed in spermatid cell plastids, which at maturity consist of only a small starch grain surrounded by the envelope. Chromoplast‐like organelles are found in the cells of the antheridial jacket in some genera; these contain numerous osmiophilic globules that are probably pigment aggregations. Colourless bead‐like plastids occur in the rhizoids; these seem to develop by fragmentation of the single chloroplast in the rhizoid initials, concomitant with the loss of chlorophyll. Chloroplast division is a tightly controlled process and, in uniplastidic species, always occurs just before nuclear division, with the participation of a unique system of chloroplast‐associated microtubules. The number of chloroplasts per cell is quite variable in some genera, although most species have but a single chloroplast in each cell of the gametophyte. Chloroplast shape is also variable from ellipsoidal, dumbbell‐shaped, to irregular. These data indicate that the anthocerote chloroplast is unique among the embryophytes and are in line with the notion of an isolated position in the plant kingdom. Certain features of chloroplast morphology appear to be typical of certain genera and might prove useful in taxonomic decisions at the generic level.

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Section: Hi Varl'vtions In Ch Lo Ropl'^st (Plastid) Ultrastructurementioning

confidence: 99%

The anthocerote chloroplast: a review

Vaughn

Ligrone²,

Owen

et al. 1992

New Phytologist

Self Cite

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“…A placental space containing crushed cells between the sporophyte and gametophyte is present not only in mosses but also in many liverworts and certain tracheophytes, while it is absent in hornworts and many tracheophytes (Gambardella and Ligrone 1987;Ligrone et al 1993;Hilger et al 2002;Duckett and Ligrone 2003;Johnson and Renzaglia 2008). This suggests a possibility that the sporophyte penetration accompanied with the degeneration of epigonium cells is a symplesiomorphic character state in land plants.…”

Section: Discussionmentioning

confidence: 88%

“…Previous studies revealed the distribution pattern of transfer cells in the mature placenta in more than 100 bryophytes Carafa et al 2003;summarized in Ligrone and Gambardella 1988b;Ligrone et al 1993;, in pteridophytes (Hilger et al 2002(Hilger et al , 2005, and the wall-ingrowth structure of the transfer cells at different developmental stages in several bryophytes (Browning and Gunning 1979a;Gambardella 1987;Gambardella and Ligrone 1987;Rushing and Anderson 1996;Yip and Rushing 1999). In a histological developmental study of the sporophyte-gametophyte junction in mosses, Roth (1969) classified the junction into six types based on the criteria of the positional relationship between foot and gametophytic organs, such as conducting strands, unfertilized archegonia and innermost perichaetial leaves.…”

Section: Introductionmentioning

confidence: 97%

Comparative development of the sporophyte–gametophyte junction in six moss species

Uzawa

Higuchi

2010

J Plant Res

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Developmental anatomy of the sporophyte-gametophyte junction in six moss species is described with special reference to sporophyte penetration into the gametophytic tissue. The sporophyte-gametophyte junction in mosses is classified into two types based on vaginula morphology: in the "true vaginula" type, the junction involves only an epigonium derived from the archegonium, and in the other "shoot vaginula" type, it involves a shoot and an epigonium. In both of the types, the sporophyte penetrates into an epigonial tissue accompanied by degeneration of epigonium cells under the developing sporophyte. In the "shoot vaginula" type, the sporophyte further penetrates into the conducting strand or similar cells that seem to be induced by stimulation of fertilization. It is likely that the difference in growth rate between the epigonium and the capped sporophyte is a mechanical force for sporophyte penetration.

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“…Ant Colony Optimization (ACO) is used to solve combinational problems such as vehicle routing [3], [4], salesman"s travel problem [5], [6], graph coloring [7], the quadratic assignment problem [8], and process planning and scheduling [9].…”

Section: Literature Reviewmentioning

confidence: 99%

Ant Colony Optimization for a Plan Guide Course Registration Sequence

Al-Qassas¹,

El-Bashir²,

AlShboul³

et al. 2018

ijacsa

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Students in universities do not follow the prescribed course plan guide, which affects the registration process. In this research, we present an approach to tackle the problem of guide for plan of course sequence (GPCS) since that sequence may not be suitable for all students due to various conditions. The Ant Colony Optimization (ACO) algorithm is anticipated to be a suitable approach to solving such problems. Data on sequence of the courses registered by students of the Computer Science Department at Al Al-Bayt University over four years were collected for this study. The fundamental task was to find the suitable pheromone evaporation rate in ACO that generates the optimal GPCS by conducting an Adaptive Ant Colony Optimization (AACO) on the model that used the collected data. We found that 17 courses out of 31 were placed in semesters differing from the semesters preset in the course plan.

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The development of the placenta in the anthocerote Phaeoceros laevis (L.) Prosk

Cited by 15 publications

References 15 publications

The anthocerote chloroplast: a review

The anthocerote chloroplast: a review

Comparative development of the sporophyte–gametophyte junction in six moss species

Ant Colony Optimization for a Plan Guide Course Registration Sequence

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