scholarly journals Ontogenetic changes of phyllotaxis in Anagallis arvensis L.

2014 ◽  
Vol 64 (4) ◽  
pp. 319-325 ◽  
Author(s):  
Dorota Kwiatkowska

During the ontogeny of <i>Anagallis</i> spontaneous changes of phyllotaxis appear in a regular sequence. The initial decussate pattern is followed by spiral Fibonacci phyllotaxis, this in turn, by a trimerous pattern, and finally Lucas spiral phyllotaxis is formed. In the course of the first and most common phyllotactic transition, from the decussate to spiral Fibonacci pattern, changes in primordia arrangement occur only within a limited sector of the apex circumference. In the complementary sector, primordia emerge as if the decussate phyllotaxis continued. It is likely that similar circumferential discontinuity accounts for further transitions. The common ontogenetic sequence of patterns in <i>Anagallis</i> is such that, theoretically, each transition requires minimal changes in shoot apex geometry. Although the meristem in <i>Anagallis</i> is able to produce primordia either in whorls or spirally, the elongated shoots of this plant seem to have leaves exclusively in whorls. It appeared that in shoots with an initially spiral pattern, leaves can be clustered in pseudo-whorls due to the uneven internode elongation. Pseudowhorls are composed usually of three (Fibonacci) or four (Lucas) leaves of successive nodes. The number of leaves in a pseudo-whorl equals the number of leaves positioned on one revolution of the ontogenetic helix, which is different in these two spiral patterns. In shoot apices with whorled phyllotaxis, the leaf and flower primordia of a whorl are of different size. On elongated shoots, flower buds emerging in the axils of leaves of one whorl also differ in size.

2014 ◽  
Vol 64 (3) ◽  
pp. 213-222 ◽  
Author(s):  
Dorota Kwiatkowska

Ontogenetic changes in the primary vasculature of <i>Anagallis</i> shoots are strictly related to phyllotaxis. During the ontogeny of <i>Anagallis</i>, whorled and spiral phyllotactic patterns appear alternately in a regular sequence. The initial decussate phyllotaxis is transformed into the spiral Fibonacci, and then further into trimerous pattern. This in turn may change into the spiral Lucas phyllotaxis. Sporadically the immediate transition from the decussate to trimerous phyllotaxis takes place. The vascular system in <i>Anagallis</i> is always closed, despite that both whorled and spiral phyllotaxes are present. Also the number of vascular traces diverging to the leaf is constant. In the course of a single phyllotactic transition, there is an increase in the number of vascular sympodia and in the number of leaf traces present in the vascular cylinder. Usually only one single sympodium and one or two traces are added to the system. The immediate addition of two sympodia occurs only during infrequent transition from the decussate to trimerous pattern. The increase in the number of sympodia is most often simultaneous with the phyllotactic transition, however, when the trimerous pattern is transformed into the spiral Lucas, the increase is delayed, sometimes for as much as ten plastochrons. In shoots with changing phyllotaxis, a sector within the vascular cylinder can be distinguished, in which the leaf traces are arranged as if the previous phyllotactic pattern continued, whereas rearrangement of traces takes place at the same level but in the complementary sector. This is in agreement with the concept of discontinuous circumferential changes in the shoot apex being responsible for qualitative transformations of phyllotaxis.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 447d-447
Author(s):  
Meriam Karlsson ◽  
Jeffrey Werner

Nine-week-old plants of Cyclamen persicum `Miracle Salmon' were transplanted into 10-cm pots and placed in growth chambers at 8, 12, 16, 20, or 24 °C. The irradiance was 10 mol/day per m2 during a 16-h day length. After 8 weeks, the temperature was changed to 16 °C for all plants. Expanded leaves (1 cm or larger) were counted at weekly intervals for each plant. The rate of leaf unfolding increased with temperature to 20 °C. The fastest rate at 20 °C was 0.34 ± 0.05 leaf/day. Flower buds were visible 55 ± 7 days from start of temperature treatments (118 days from seeding) for the plants grown at 12, 16, or 20 °C. Flower buds appeared 60 ± 6.9 days from initiation of treatments for plants grown at 24 °C and 93 ± 8.9 days for cyclamens grown at 8 °C. Although there was no significant difference in rate of flower bud appearance for cyclamens grown at 12, 16, or 20 °C, the number of leaves, flowers, and flower buds varied significantly among all temperature treatments. Leaf number at flowering increased from 38 ± 4.7 for plants at 12 °C to 77 ± 8.3 at 24 °C. Flowers and flower buds increased from 18 ± 2.9 to 52 ± 11.0 as temperature increased from 12 to 24 °C. Plants grown at 8 °C had on average 6 ± 2 visible flower buds, but no open flowers at termination of the study (128 days from start of treatments).


2016 ◽  
Vol 85 (4) ◽  
Author(s):  
Takuya Okabe

Phyllotaxis studies published in German in the 1930s have reported intriguing regularity in the arrangement of incipient leaves on shoot apices of a wide variety of plant species. However, these studies have received little attention today, even though they provide a crucial evidence base for understanding this mathematical phenomena. Here I recapitulate the essential point by means of illustrative examples. It is emphasized that accurate control of apical divergence angle is at the heart of the numerical riddle of spiral phyllotaxis. The accurate patterning at the shoot apex has an unexpected evolutionary benefit of being optimally adaptive in the subsequent events of phyllotactic change to occur on an elongating shoot.


Irriga ◽  
2017 ◽  
Vol 22 (2) ◽  
pp. 204-219 ◽  
Author(s):  
Mariana Lays Andrade Oliveira ◽  
Vital Pedro da Silva Paz ◽  
Karoline Santos Gonçalves ◽  
Greice Ximena Santos Oliveira

Crescimento e Produção de girassol ornamental irrigado com diferentes lâminas E diluições de água residuária  MARIANA LAYS ANDRADE OLIVEIRA¹; VITAL PEDRO DA SILVA PAZ²; KAROLINE SANTOS GONÇALVES³ E GREICE XIMENA SANTOS OLIVEIRA4 ¹Núcleo de Engenharia de Água e Solo, Universidade Federal do Recôncavo da Bahia, UFRB, Cruz das Almas, BA, [email protected]²Programa de Pós-Graduação em Engenharia Agrícola, Universidade Federal do Recôncavo da Bahia, UFRB, Cruz das Almas, BA, [email protected]³Programa de Pós-Graduação em Engenharia Agrícola, Universidade Federal do Recôncavo da Bahia, UFRB, Cruz das Almas, BA, [email protected] do Meio Ambiente e Recursos Hídricos do Estado da Bahia, Salvador, BA, [email protected]  1 RESUMO O objetivo deste trabalho foi avaliar o crescimento e a produção de girassol ornamental submetido à irrigação com diferentes lâminas e diluições de água residuária. O experimento foi conduzido em delineamento experimental inteiramente casualizado em esquema fatorial 5x4 com 4 repetições, em casa de vegetação no Núcleo de Engenharia de Água e Solo (NEAS), pertencente à Universidade Federal do Recôncavo da Bahia, localizada no município de Cruz das Almas - BA. A cultivar utilizada foi a Anão de Jardim e os tratamentos foram constituídos por cinco concentrações de água residuária diluídas em água de abastecimento (0, 25, 50, 75 e 100%) e quatro lâminas de irrigação obtidas a partir das percentagens de evaporação do tanque classe A (70, 90, 110 e 130%). As variáveis analisadas foram: altura da planta (AP), diâmetro do caule (DC), número de folhas (NF), massa fresca e seca da parte aérea (MFPA e MSPA), dias para o aparecimento de botões florais (DABF), dias para o período de floração (DPF), dias para abertura total dos capítulos (DATC), diâmetros internos e externos dos capítulos (DI e DE), massa fresca e seca dos capítulos (MFC e MSC), além da estimativa do consumo hídrico da planta (CH). Os resultados obtidos mostraram que, com exceção da AP, todas as variáveis foram influenciadas pelas lâminas de irrigação ou pelas diluições de água residuária, não havendo influência significativa da interação entre os fatores para nenhuma das variáreis avaliadas. O uso de água residuária e a lâmina de 110% da evaporação do tanque classe A favoreceram o desenvolvimento do girassol. O menor e maior consumo hídrico da cultura foi observado nas lâminas de 70 e 130%, respectivamente. Palavras-chave: Reuso, cv. Anão de jardim, tanque Classe A.  OLIVEIRA, M. L. A.; PAZ, V. P. da S.; GONÇALVES, K. S.; OLIVEIRA, G. X. S.GROWTH AND PRODUCTION OF ORNAMENTAL SUNFLOWER IRRIGATED WITH DIFFERENT DEPTHS AND CONCENTRATIONS OF WASTEWATER    2 ABSTRACT The aim of this study was to evaluate the ornamental sunflower production subjected to different depths and concentration of wastewater. The experiment was conducted in experimental design completely randomized in a factorial 5x4 with 4 repetitions in a greenhouse at the Center of Water and Soil Engineering (NEAS), of the Federal University of Recôncavo da Bahia, located in Cruz das Almas, BA, Brazil. The cultivar used was cv. Anão de Jardim and the treatments consisted of five wastewater concentrations diluted in water supply (0, 25, 50, 75 and 100%) and four irrigations blades obtained through evaporation of the percentages of the class A pan (70, 90 , 110 and 130%). The variables analyzed were: plant height (AP), stem diameter (DC), number of leaves (NF), fresh and dry weight of the aerial part (MFPA and MSPA), days for the appearance of flower buds (DABF), days to flowering period (DPF), days for full opening of chapters (DATC), internal and external diameters of the chapters (DI and DE), fresh and dry weight of chapters (MFC and MSC), and the estimate of water consumption plant. The results showed that, except for the AP, all variables were influenced by the irrigation blades or the wastewater concentrations, and there was no significant influence of interaction between factors for any evaluated variables. The use of wastewater and 110% evaporation of the class A pan depth favored the development of sunflower. The lower and higher water consumption of the culture was observed in depths 70% and 130%, respectively. Keywords: reuse, cv. Anão de Jardim, class A pan.


2018 ◽  
Vol 10 (6) ◽  
pp. 171
Author(s):  
João Everthon da Silva Ribeiro ◽  
Arliston Pereira Leite ◽  
José Eldo Costa ◽  
Manoel Bandeira de Albuquerque ◽  
Fábio Mielezrski

Among nutrients, nitrogen is required in the greatest quantities by bean culture. The objective of this work was to evaluate growth, physiological responses and productivity of the common bean cultivar, ‘IAC Imperador’ under varying nitrogen doses in Brejo Paraibano. The experiment was carried out at Fazenda Experimental Chã-de-Jardim (Chã-de-Jardim Experimental Farm), of the Centro de Ciências Agrárias of the Universidade Federal da Paraíba, in the municipality of Areia, state of Paraíba. The treatments comprised 0, 50, 100, 150 and 200 kg of nitrogen ha-1, applied in coverage at 35 days after sowing. To assess growth, plant height, stem diameter and number of leaves were evaluated. For gas exchange, photosynthesis rate, internal CO2 concentration, transpiration, stomatal conductance, instantaneous water use efficiency and instantaneous carboxylation efficiency were evaluated. For chlorophyll “a” fluorescence, minimum leaf fluorescence, maximum leaf fluorescence, variable maximum fluorescence, potential quantum efficiency of PSII (Photosystem II) and ratio (Fv/F0) were evaluated. For the components of primary productivity, the height of insertion of the first pod, number of pods per plant and the number of grains per pod were evaluated. Nitrogen fertilization in coverage significantly affected most of the growth, gas exchange and productivity variables, with the dose of 200 kg ha-1 being responsible for the highest values (p < 0.05). Chlorophyll fluorescence showed no significant differences among the nitrogen doses. The nitrogen doses influenced the growth, gas exchange and productivity of the common bean in the region of Brejo Paraibano. 


Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 758 ◽  
Author(s):  
Sunho Park ◽  
Kyoung Soon Choi ◽  
Sujin Kim ◽  
Yonghyun Gwon ◽  
Jangho Kim

The control and promotion of plant and crop growth are important challenges globally. In this study, we have developed a nanomaterial-assisted bionic strategy for accelerating plant growth. Although nanomaterials have been shown to be toxic to plants, we demonstrate herein that graphene oxide can be used as a regulator tool for enhancing plant growth and stability. Graphene oxide was added to the growth medium of Arabidopsis thaliana L. as well as injected into the stem of the watermelon plant. We showed that with an appropriate amount provided, graphene oxide had a positive effect on plant growth in terms of increasing the length of roots, the area of leaves, the number of leaves, and the formation of flower buds. In addition, graphene oxide affected the watermelon ripeness, increasing the perimeter and sugar content of the fruit. We believe that graphene oxide may be used as a strategy for enabling the acceleration of both plant growth and the fruit ripening process.


2019 ◽  
Vol 72 (3) ◽  
pp. 8927-8935 ◽  
Author(s):  
Alexander Calero Hurtado ◽  
Yanery Pérez Díaz ◽  
Dilier Olivera Viciedo ◽  
Elieni Quintero Rodríguez ◽  
Kolima Peña Calzada ◽  
...  

The use of Efficient Microorganisms (EM) can be an effective alternative to improve plant growth and yield in the bean cultivation. Therefore, different forms of application of efficient microorganisms were evaluated in the production of two cultivars of the common bean from November of 2013 to March of 2014. Two factors were studied; the first one was comprised of the two cultivars, Velazco Largo (VL) and Cuba Cueto (CC-25-9-N). The second factor consisted of four treatments with EM; without EM (control), soil inoculation (100 mL L-1), foliage applications (100 mL L-1), and the combined soil inoculation (100 mL L-1) plus foliar applications (100 mL L-1). The experiment was carried out in a randomized block design, in factorial outline 2×4, with three repetitions. The agronomic indicators were evaluated as the number of leaves per plant, the height of plants, number of pods per plant, number of seeds per pod, the mass of 100 seeds (g) and the yield (t ha-1). The results showed that the different forms of application of efficient microorganisms stimulated the agronomic indicators evaluated in both crops. The associated applications between the inoculation of the soil and foliage applications of efficient microorganisms provided better results, producing increments in the yield of 1.13 t ha-1 in VL and 2.15 t ha-1 in CC-25-9-N.


2012 ◽  
Vol 60 (1) ◽  
pp. 79 ◽  
Author(s):  
S. Z. Tesfay ◽  
I. Bertling ◽  
J. P. Bower ◽  
Carol Lovatt

D-Mannoheptulose (D-manno-2-heptulose) and perseitol (D-glycero-D-manno-heptose) are unusual seven-carbon (C7) sugars that have been postulated to act as storage and transport sugars in avocado. However, thus far, there is no published evidence that satisfactorily explains the physiological functions of these carbohydrates. Various tissues at different stages of the avocado life-cycle were therefore analysed for C7 carbohydrates to derive clues on the function of the six-carbon (C6) and C7 sugars. Adult reproductive tissues (flower buds and fruit) contained significantly greater concentrations of C7 than C6 sugars, whereas in juvenile avocado tissue, the classic C6 storage carbohydrate, starch, was found only in developing and mature seeds, predominatly in the cotyledons. The dramatic increase in shoot and cotyledon C7-sugar concentrations, together with a reduction of starch reserves in the cotyledons as a result of lack of light during germination, suggests that the C6 storage carbohydrate (CHO) starch can be converted to fuel the C7 metabolism. Therefore, a changeover from C6 carbohydrate to C7 sugar metabolism characterises the progression from juvenility to maturity in avocado. Avocado seems to mirror its evolutionary development characterised by a switch-over from the common C6- to a specialised C7-sugar metabolism in the juvenile versus adult tissue. The dominance of C7 carbohydrates over C6 in adult tissues is, therefore, due to the fact that C7 sugars have multifunctional roles as a source of energy and anti-oxidants.


1967 ◽  
Vol 45 (7) ◽  
pp. 955-959 ◽  
Author(s):  
Sidki Sadik ◽  
J. L. Ozbun

Cauliflower plants were induced to flower after being grown at 42 °F for varying periods of time, depending on the cultivar. Some of the histochemical changes in the shoot apex at the beginning of, during, and after floral induction were studied. During floral induction there is about a 20-fold increase in the volume of nucleoli and about a 3-fold increase in volume of nuclei. Apices of vegetative plants stained with bromophenol blue at pH 2.3, show small and dense nucleoli, dense and granular nuclei, and a small amount of weakly staining cytoplasm. In contrast, cells of apices of induced plants stained with bromophenol blue at pH 2.3, show large and dense nucleoli, large and weakly staining nuclei; however, these cells contain more and denser cytoplasm. Sections of vegetative and induced apices stained with alkaline fast green stained differently from those stained with bromophenol blue. Nucleoli did not stain and cytoplasm stained faintly with fast green while chromosomes stained strongly. Deoxyribonucleic acid (DNA) content of vegetative and induced apices are similar. Shoot apices of vegetative plants contained little or no starch. However, shoot apices of plants grown at 42 °F accumulate large amounts of starch. Floral primordia which develop into functional flowers are glutted with starch, while floral primordia which abort are void of starch.


HortScience ◽  
1993 ◽  
Vol 28 (8) ◽  
pp. 831-832
Author(s):  
Sorkel A. Kadir ◽  
Ed L. Proebsting

Differential thermal analysis (DTA) was used to measure deep supercooling in flower buds of Prunus dulcis Mill., P. armeniaca L., P. davidiana (Carr.) Franch, P. persica (L.) Batsch, three sweet cherry (P. avium L.) selections, and `Bing' cherries (P. avium L.) during Winter 1990-91 and 1991-92. Low temperatures in Dec. 1990 killed many flower buds. After the freeze, dead flower primordia continued to produce low-temperature exotherms (LTEs) at temperatures near those of living primordia for >2 weeks. In Feb. 1992, cherry buds that had been killed by cooling to -33C again produced LTEs when refrozen the next day. As buds swelled, the median LTE (LTE50) of dead buds increased relative to that of living buds, and the number of dead buds that produced LTEs decreased. LTE artifacts from dead flower priimordia must be recognized when DTA is used to estimate LTE50 of field-collected samples.


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