Selfed-seed production depending on individual size and flowering sequence in Iris gracilipes (Iridaceae)

2002 ◽  
Vol 80 (10) ◽  
pp. 1096-1102 ◽  
Author(s):  
Takashi Kimura ◽  
Hiroshi S Ishii ◽  
Satoki Sakai
Keyword(s):  
Seed Production ◽  
The Other ◽  
Perennial Herb ◽  
Pollination Experiments ◽  
Selfed Seed ◽  
Other Hand ◽  
Hand Pollination ◽  
Self Fertilization ◽  
Individual Size

To examine the influence of individual size and time of pollination on selfed and outcrossed seed production, we conducted hand-pollination experiments in 2000 and 2001 in the perennial herb Iris gracilipes A. Gray (Iridaceae). Small individuals produced outcrossed seeds to a greater extent than selfed seeds, whereas large individuals produced not only outcrossed seeds but also selfed seeds. On the other hand, when half of all flowering shoots of an individual were removed, both selfed and outcrossed seeds were produced independent of individual size. Flowers that opened earlier within the same flowering shoots were likely to produce outcrossed seeds, while those that opened later within the same flowering shoots produced relatively more selfed seeds than did the flowers which opened earlier. Thus, the ratio of the numbers of selfed to outcrossed seeds produced may differ between small and large individuals. These results suggest that plants regulate selfed- and outcrossed-seed production depending on their sizes and flowering sequence.Key words: self-fertilization, individual size, flowering sequence, Iris gracilipes.

scholarly journals PRODUKSI POLONG DAN BIJI TANAMAN GAMAL (Glirisidia sepium) DARI BERBAGAI PROVENANSI DENGAN PEMUPUKAN NPK

PERENNIAL ◽  
2006 ◽  
Vol 2 (1) ◽  
pp. 21
Author(s):  
Muh. Restu ◽  
Baharuddin Mappangaja
Keyword(s):  
Natural Resources ◽  
Seed Production ◽  
Forest Productivity ◽  
The Other ◽  
Other Hand ◽  
Average Production ◽  
Biological Reproduction

The productivity of forest natural resources is now decreasing and therefore rehabilitation efforts is urgently needed. Breeding of forest plant is the best solution to increase forest productivity in both quantity and quality. The biological reproduction can be conducted through seed production with fertilization. This research was aimed at determining the effect of fertilizing treatments on pod and seed production of different Glirisidia sepium provenances to find out the best provenance and best fertilizer dosage. Fertilization treatments showed a significant effect on the pod and seed production. On the other hand, the provenance and its interaction with fertilizing did not show any significant effects on the pod and seed production. The best performance was found on the fertilization treatment of 500 g resulting in the average production of 1,288 pods and 27,621 seeds/tree. Keywords: Fertilizing, Seed Production, Provenance, Glirisidia sepium

Cytogenetics of Hybrids Among Perennial Species of Glycine Subgenus Glycine

1979 ◽  
Vol 27 (6) ◽  
pp. 713 ◽  
Author(s):  
E Putievsky ◽  
P Broue
Keyword(s):  
Cytogenetic Analysis ◽  
Diploid Species ◽  
The Other ◽  
F1 Hybrids ◽  
Pollen Stainability ◽  
Perennial Species ◽  
Tetraploid Form ◽  
Other Hand ◽  
Self Fertilization

A cytogenetic analysis based on F1 hybrids of some of the perennial species of Glycine subgenus Glycine Verdc. shows that G. clandestina and G. canescens are closely related and further, that either one of these diploid species could have provided one genome for the tetraploid form of G. tomentella. On the other hand, it appears that G. falcata and G. tabacina are distinctive species which are not closely related to the other three species. The tetraploid form of G. tomentella is genetically heterogeneous and crosses between certain types yield F1s with low pollen stainability which fail to set seed under conditions of self-fertilization.

Functional differentiation in pollination processes between the outer and inner perianths in Iris gracilipes (Iridaceae)

2006 ◽  
Vol 84 (1) ◽  
pp. 164-171 ◽  
Author(s):  
Shin-Ichi Morinaga ◽  
Satoki Sakai
Keyword(s):  
Genetic Correlation ◽  
Seed Production ◽  
Pollen Grains ◽  
Functional Differentiation ◽  
The Other ◽  
Pollination Success ◽  
Other Hand ◽  
Pollen Removal

We examined the functional differentiation in pollination processes between the outer and inner perianths in Iris gracilipes A. Gray flowers. We manipulated the length of the outer and inner perianths and examined the effect on the following: number of pollinator approaches to, and landings on, flowers; pollen removal and deposition during a single pollinator visit; total number of pollen grains removed; and seed production. The outer perianths contributed to the functions of pollinator approach and landing, pollen removal, and seed production, but not to mechanical fitting of pollinators. Since flowers with shortened outer perianths gained less pollination success than control flowers, and since lengthening of outer perianths did not enhance pollination success, the length of the outer perianths might have evolved as an adaptive characteristic. On the other hand, the inner perianths contributed to the functions of pollinator approach and pollen removal but not to pollinator landing, mechanical fitting of pollinators, nor seed production. Since flowers with shortened inner perianths gained pollination success similar to that of control flowers, the adaptive length of the inner perianths may be shorter than what is found in present-day flowers. We propose that genetic correlation between the outer and the inner perianths might prevent shortening of the inner perianths.

Seed Production System in Romania

2013 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
Najah Naiem Mutlak
Keyword(s):  
Seed Production ◽  
Production System ◽  
The Other ◽  
Cereal Crops ◽  
Other Hand ◽  
The One

This paper aims at presenting the structure of varieties and the evolution of consumption of seeds for main cereal crops. Analyzing the number of varieties and hybrids, it may be noticed that there is a growing trend. In Romania, the quantities of seeds used were variable, depending, on the one hand of the importance and expansion of the crop, and, on the other hand, on the records existing in the seed chain. For Romania, looking at the overall practices applied in relation to seed utilization a growing trend was noticed with respect to using seeds for wheat crops, but also a drop of barley and maize crops, besides the annual fluctuating consumption levels. By correlating the factors (areas and amounts of seeds) with production that may be obtained a growing trend for wheat and barley was noticed and a decreasing trend for maize.

Limitations on reproduction in alpine Ranunculus acris

1997 ◽  
Vol 75 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Ørjan Totland
Keyword(s):  
Seed Production ◽  
Resource Availability ◽  
Seed Weight ◽  
Pollen Limitation ◽  
Resource Limitation ◽  
Limiting Factors ◽  
Perennial Herb ◽  
Plant Variation ◽  
Hand Pollination ◽  
Ranunculus Acris

This study examines experimentally the influence of limiting factors on seed to ovule ratio and seed weight in three alpine populations of the perennial herb Ranunculus acris L. at Finse, southwest Norway. To test for pollen and resource limitation, seed production of supplementally pollinated or completely defoliated plants was compared to that of untreated plants. In one population the experiment was repeated twice during the season. In mid-season, supplemental hand-pollination had no significant effect on seed to ovule ratio, but significantly increased the seed weight, whereas complete defoliation resulted in a significant decrease in seed to ovule ratio and a marginally significant decrease in seed weight. These results indicate that pollen limitation occurred on seed weight and resource limitation mainly on seed to ovule ratio. Seed production in late-flowering control and defoliated plants in one population was nearly completely absent, whereas supplemental pollination increased seed production substantially. Most seeds were produced at the lowest elevation, and frost damage on developing seeds was most pronounced at the highest elevation population, suggesting that severe weather conditions at the highest altitudes had a negative influence on reproductive processes. Significant positive relationships between seed number and seed weight were found, possibly reflecting a large among-plant variation in total resource availability. Key words: altitude gradient, climate, defoliation, pollen and resource availability, seasonal variation, seed size.

scholarly journals Geographical and seasonal distributions of the seedeaters Sporophila bouvreuil and Sporophila pileata (aves: Emberizidae)

2010 ◽  
Vol 50 (32) ◽  
pp. 517-533 ◽  
Author(s):  
Érika Machado ◽  
Luís Fábio Silveira
Keyword(s):  
Seed Production ◽  
Breeding Season ◽  
Atlantic Forest ◽  
Short Distance ◽  
Movement Patterns ◽  
The Other ◽  
Southern Brazil ◽  
Migration Patterns ◽  
Other Hand ◽  
Resident Populations

Many species in the genus Sporophila are migratory. Migration patterns, while poorly studied, may be influenced by seed production which can be very seasonal in some regions. The distribution of S. bouvreuil extends from the Amazon and Suriname south through a large part of the open regions of Brazil. Sporophila pileata, on the other hand, is found in southeastern and southern Brazil as well as Argentina and Paraguay. Both of these species migrate, but their movement patterns are poorly known. To better understand the geographical and the seasonal distributions of S. bouvreuil and S. pileata, we grouped the records into two categories: the breeding season (September to March) and the putative migration season (April to August). We found two areas of sympatry between S. bouvreuil and S. pileata in the Brazilian states of Minas Gerais and São Paulo. For S. bouvreuil we suggest that populations that breed in the Amazon migrate to the Cerrado or Caatinga, where they will encounter resident populations of the same species. These resident populations may take part in short distance migrations. Sporophila pileata, on the other hand, occur in the Cerrado and open areas within the Atlantic Forest and it is not yet possible to determine migratory tendencies or destinations in the non-breeding season.

Selective Fruit Abortion in Grevillea barklyana (Proteaceae)

1993 ◽  
Vol 41 (5) ◽  
pp. 499 ◽  
Author(s):  
F Harriss ◽  
RJ Whelan
Keyword(s):  
Breeding System ◽  
Fruit Set ◽  
Pollen Tubes ◽  
The Other ◽  
Limited Resources ◽  
Pollination Experiments ◽  
Cross Pollination ◽  
Hand Pollination ◽  
Fruit Abortion ◽  
Natural Pollination

The breeding system of Grevillea barklyana F. Muell. ex Benth. was studied using experimental hand pollinations. Fruit set was generally low (less than 5%), and equivalent for autogamy, self-pollination, outcross-pollination and inflorescences left exposed to natural pollination. Pollen tubes were produced in only a low proportion of flowers in the autogamy treatment, with few pollen tubes per flower and short pollen tubes in styles at both 24 and 48 h after anthesis. Selfing and cross-pollination produced equal numbers of pollen tubes in an equivalent and high proportion of flowers (ranging from 40% to 80%). However, pollen tubes resulting from selfing were shorter than from outcrossing after 24 and 48 h. Hand pollination experiments in which half of the flowers on inflorescences were pollinated with self pollen and the other half with outcross pollen generally produced a slightly skewed pattern of fruit set, with a higher proportion of the outcrossed flowers setting fruit. The following processes could contribute to the selective development of outcrossed fruit in this self-compatible species: (1) pollen tubes from outcrossed pollinations reach ovules before those growing from self pollen; (2) fruits that start to develop first obtain first call on limited resources; (3) fruits that are initiated later abort when other fruits on an inflorescence are developing.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

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