The effect of photoperiod on the growth and development of Echinochloa spp. Millets

1985 ◽  
Vol 25 (2) ◽  
pp. 428 ◽  
Author(s):  
DK Muldoon
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Growth And Development ◽  
Apical Meristem ◽  
Leaf Number ◽  
Relative Growth ◽  
Short Day ◽  
Crop Development ◽  
Abnormal Head ◽  
Main Tiller

Two cultivars of Echinochloa utilis, Ohwi et Yabuno, and one E.frumentacea (Roxb.) Link cultivar were grown in a glasshouse under three photoperiod regimes: naturally varying photoperiods (1 2-1 3 h), and fixed photoperiods of 14 and 16 h. Both species behaved as quantitative short-day plants although, in E. utilis, extending the photoperiod from 14 to 16 h delayed head emergence disproportionately. The delay in head emergence did not affect the relative growth rate, and longer photoperiods led to higher shoot weights; main tiller leaf number increased only slightly. The commencement of apical meristem elevation was delayed under longer photoperiods, a feature believed to be beneficial to regrowth. A time-of-sowing study in the field illustrated the effect of this short-day response upon crop development. Sixteen introduced E. utilis cultivars and 10 E. frumentacea cultivars also behaved as quantitative short-day plants. Within each species there were differences between cultivars in sensitivity to photoperiod. Some cultivars of E. utilis were very late and had abnormal head emergence at 16 h. Latitudinal effects on the performance of these cultivars are discussed.

scholarly journals Effects of photoperiod and light spectra on growth and pigment composition of the green macroalga Codium tomentosum

2020 ◽  
Author(s):  
Rúben Marques ◽  
Sónia Cruz ◽  
Ricardo Calado ◽  
Ana Lillebø ◽  
Helena Abreu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Blue Light ◽  
Early Development ◽  
Red Light ◽  
Pigment Composition ◽  
Relative Growth ◽  
Light Spectra ◽  
Short Day ◽  
Long Day

Abstract Codium tomentosum is a marine green macroalga with multiple value-added applications that is being successfully used as an extractive species in sustainable integrated multi-trophic aquaculture systems. Nonetheless, growth conditions of this species at an early development phase still require optimization. The present study addresses, under controlled laboratory conditions, the effects of photoperiod (long vs. short-day) and light spectra (white, blue, and red light) on growth and pigment composition of C. tomentosum. Relative growth rate was approximately 2× higher under long-day photoperiod (average of 39.2 and 20.1% week−1 for long and short-day, respectively). Concentrations per dry weight of major pigments such as chlorophyll a (Chla) and siphonoxanthin (Siph) were significantly higher under long-day photoperiod. Relative growth rates were higher under red light, intermediate under white light, and lower under blue light. These last results were rather surprising, as Siph-Chla/Chlb light harvesting complexes of Codium have increased absorption in the blue-green region of the light spectra. Changes in carbon allocation patterns caused by the spectral composition of light and overgrowth of green microalgae in blue light cultures could explain the differences recorded for relative growth rate. Long-day photoperiod and light sources with preferential emission at the red region of the light spectra were identified as optimal for growth of C. tomentosum at early development stages. These lighting conditions can reduce the time required to reach the necessary biomass before transfer to grow-out systems. Overall, these findings can shorten production time, increase macroalgal productivity, and enhance aquaculture revenues.

scholarly journals Growth of the crabgrass species Digitaria ciliaris and Digitaria nuda

2012 ◽  
Vol 30 (2) ◽  
pp. 317-325 ◽  
Author(s):  
R.C. Souza ◽  
A.C. Dias ◽  
M.R.A. Figueiredo ◽  
F.E.B. Obara ◽  
P.J Christoffoleti
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Dry Matter ◽  
Area Ratio ◽  
Leaf Area Ratio ◽  
Leaf Number ◽  
Relative Growth ◽  
Absolute Growth Rate ◽  
Absolute Growth

The aim of this research paper was to compare the growth of D. ciliaris and D. nuda crabgrass species under non-competitive conditions. To this end, two experiments were conducted, one from March - July 2010 and the other from February - June 2011. The experimental design of both trials was completely randomized making a factorial (2 seasons x 2 species crabgrass x 12 evaluation periods) with four replications. Assessments began at 15 days after sowing (DAS), and repeated weekly until 92 DAS. The variables evaluated were total dry matter (roots+leaves+stems), leaf area, leaf number and tiller. The results were submitted to analysis of variance and the absolute growth rate, relative growth rate and leaf area ratio were calculated using the means, which were adjusted regression models. The crabgrass species were significantly different in leaf area, leaf number, tiller number and dry matter per plant. D. ciliaris for all variables was statistically higher than D. nuda. Regarding the speed at which the growth of the species occurred, the absolute growth rate and relative growth rate of D. ciliaris was also greater than D. nuda. In addition, D. ciliaris also had a lower leaf area ratio indicating greater efficiency in converting light energy into carbohydrates. It can be concluded that D. ciliaris has a higher growth rate in conditions where there is no limitation of nutrients and water availability in relation to D. nuda, mainly due to D. ciliaris have greater leaf area, number of leaves and dry matter accumulation per plant.

Growth and seasonality of seedlings and juveniles of primary species of a cloud forest in northern Venezuela

1992 ◽  
Vol 8 (3) ◽  
pp. 299-305 ◽  
Author(s):  
Saúl Flores
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Forest Canopy ◽  
Slow Growth ◽  
Cloud Forest ◽  
Primary Root ◽  
Leaf Number ◽  
First Year ◽  
Leaf Production ◽  
Relative Growth

ABSTRACTThe survival, height and leaf production of seedlings and juveniles of Aspidosperma fendleri and Richena grandis were measured monthly for three years after germination. During the first year, some seedlings and juveniles of Aspidosperma fendleri were collected and the number of rootlets, the primary root length and the shoot: root ratio were determined.Both species show periodicity in growth but their relative growth rate differs between species. For Aspidosperma fendleri, the highest relative growth rate (0.313 y-1) was found for individuals grown under greenhouse conditions followed by individuals growing in an old forest gap (0.143 y-1) and finally individuals under the forest canopy (0.137 y-1). For Richeria grandis, the relative growth rate under the forest canopy was 0.261 y-1. Leaf production for Aspidosperma fendleri in the forest (natural conditions) was 4.39 total mean leaf number for five years and 5.46 total mean leaf number under greenhouse conditions. For Richeria grandis it was 5.34 mean leaf production for four years. The root: shoot ratio for Aspidosperma fendleri was constant during the observation year. Aspidosperma fendleri showed a lower number of rootlets than did Richeria grandis. There was an inverse relationship between growth and survival during the dry season. During this period, mortality was higher and the highest mortality occurred during the first year when the total relative growth rate was highest.Slow growth is evident in both species. This mechanism may represent an adaptive advantage to remain dormant until there is an opening in the forest canopy. Since the seeds of Aspidosperma fendleri and Richeria grandis are highly vulnerable to predators and pathogens, slow growth as seedlings and juveniles allows them to survive, and contributes to regeneration in cloud forest.

Effect of Photoperiod on Growth and Development of Cassava (Manihot esculenta Crantz)

1985 ◽  
Vol 12 (6) ◽  
pp. 621 ◽  
Author(s):  
BA Keating ◽  
GL Wilson ◽  
JP Evenson
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Growth And Development ◽  
Day Treatment ◽  
Storage Root ◽  
Storage Roots ◽  
Manihot Esculenta Crantz ◽  
Dry Matter Partitioning ◽  
Relative Growth ◽  
Controlled Environments

Effects of photoperiod on growth and development of cassava were studied in controlled environments. Plants of cultivars M Aus 7 and M Aus 10 were grown under short (10-h) and long (16-h) photoperiods and harvested at approximately weekly intervals for a period of 13 weeks. Long photoperiods resulted in large increases in leaf area through increases in both number (both cultivars) and size of leaves (M Aus 7 only). The timing, extent and anatomical characteristics of storage root initiation were similar for both cultivars under 10-h and 16-h photoperiods but the subsequent balance between shoot and storage root growth strongly favoured shoot growth in long days. Dry matter partitioning followed a simple allometric pattern with the proportionality between the relative growth rate of shoots and the relative growth rate of storage roots remaining constant with time but being altered by photoperiod. Distribution to storage roots was quantitatively reduced in another experiment using M Aus 10 with each additional 1-h increment from 10-h to 16-h photoperiods. A treatment consisting of a short day (10 h) plus a 1-h night break in the middle of the dark period produced growth similar to long day treatment. Differences in cultivar response (Ceiba, CMC 84 and M Aus 7) to a range of photoperiods (11, 12, 13 and 14 h) were detected in a third experiment. The possible mechanisms and significance of these responses are discussed.

Does growth rate determine leaf form in Pisum sativum?

1989 ◽  
Vol 67 (9) ◽  
pp. 2590-2595 ◽  
Author(s):  
Kevin S. Gould ◽  
Elizabeth G. Cutter ◽  
J. Peter W. Young
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Vertical Displacement ◽  
Significant Rise ◽  
Leaf Primordium ◽  
Relative Growth ◽  
Leaf Extension ◽  
Mutant Pea

We have examined the long-standing hypothesis that leaves are morphologically more complex following prolonged proximity to the shoot apical meristem. Growth rates of the petiole and rachis of conventional and mutant pea leaves were compared for successive nodes of insertion in seedling plants. Leaves were longer at higher nodes, though the relative growth rate did not vary. Mature afila leaves were longer than those of conventional and tendril-less genotypes. The afila leaf alone exhibited a transient, highly significant rise in relative growth rate during the plastochron interval P4.5–P5.5. This rise occurred after the stage at which leaves of the different genotypes were anatomically distinguishable (stage P2–P3). Rates of vertical displacement of the leaf primordium from the shoot apical meristem did not differ significantly among genotypes. Our data suggest that the rate of leaf extension is one of the consequences, rather than a cause, of leaf morphology.

The Genesis of Form in Casuarinaceae

1985 ◽  
Vol 33 (5) ◽  
pp. 563 ◽  
Author(s):  
RF Williams ◽  
RA Metcalf
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Shoot Apex ◽  
Growth And Development ◽  
Three Dimensional ◽  
Axillary Buds ◽  
Relative Growth ◽  
Rates Of Growth

The growth and development of the shoot apex of Casuarina distyla, in which the leaves commonly occur in whorls of 6-8 members, is described. The mature apex of C. torulosa, a species with only four leaves per whorl, is also described. Stages in the development of the apex of C. distyla are illustrated with three-dimensional scale drawings. The fused stem-and-leaf nature of the vegetative axis is recognized and the growth of the blade, tube and buttress portions of the axes is presented in units of length and volume. Stages in the development of axillary buds are illustrated with three-dimensional scale drawings. Phyllotactic parameters for whorled systems of phyllotaxis in Nerium and Casuarina are presented along with those for decussate systems in Eucalyptus. The role of physical constraint in the genesis of form and the determination of rates of growth in shoot apices are discussed and it is suggested that rapid maturation of tissues may contribute to the continuous fall in the relative growth rate of the leaves.

scholarly journals PENGARUH EKSTRAKSI BIJI DAN KOMBINASI MEDIA TANAM TERHADAP PENYEMAIAN LABAN (Vitex pinnata L. Kuntze)

2019 ◽  
Vol 12 (1) ◽  
pp. 89-95
Author(s):  
Hartina Hartina ◽  
Ratna Kusuma ◽  
Dwi Susanto
Keyword(s):  
Growth Rate ◽  
Plant Height ◽  
Relative Growth Rate ◽  
Dry Weight ◽  
Germination Percentage ◽  
Leaf Number ◽  
Relative Growth ◽  
Seed Growth ◽  
Seed Extraction ◽  
Wet Weight

AbstrakPenyemaian laban dengan menggunakan metode ekstraksi biji belum banyak dilakukan dan perlu penambahan bahan pembenah tanah untuk meningkatkan pertumbuhan semai. Penelitian ini bertujuan untuk mengetahui pengaruh ekstraksi biji dan kombinasi media tanam terhadap penyemaian laban (Vitex pinnata L. Kuntze). Penelitian ini menggunakan rancangan acak lengkap dengan 2 faktor perlakuan yaitu ekstraksi biji (A0= ekstraksi basah dan A1= ekstraksi kering) dan kombinasi media tanam (M0= Tanah, M1= tanah + pasir, M2= tanah + kompos, M3= tanah + cocopeat), masing-masing diulang sebanyak 3 kali. Data yang diperoleh dianalisis dengan menggunakan uji varian (ANOVA) dengan taraf kepercayaan 95%, uji lanjut menggunakan uji Duncan pada taraf kepercayaan 95%. Hasil penelitian menunjukkan pada perlakuan ekstraksi biji kering dapat meningkatkan rata-rata persentase berkecambah sebesar 65,83% dan kecepatan tumbuh biji sebesar 3,25%, namun belum dapat meningkatkan pertambahan tinggi tanaman, jumlah daun, berat basah akhir, berat kering akhir dan laju pertumbuhan relatif. Kombinasi jenis media tanam tanah + kompos dapat meningkatkan persentase berkecambah sebesar 73,33% dan kecepatan tumbuh benih sebesar 3,40%. Penelitian ini sangat penting dalam penyiapan bibit siap tanam dalam budi daya V. pinnata.Abstract Seedling using seed extraction method has not been explored much and it needs to add soil enhancers to increase seedling growth. This research aims to determine the effect of seed extraction and combinations of planting media to seeding Laban (Vitex pinnata L. Kuntze). This research used a complete randomized design with two treatment factors namely seed extraction (A0= wet extraction, A1= dry extraction) and combinations of plant medium (M0= soil, M1= soil + sand, M2= soil + compost, M3= soil + cocopeat) were repeated three times each. The data were analyzed by using variance test (ANOVA) at 95% level of confidence and continued using Duncan test at 95% level of confidence. The result showed that the dry seed extract treatment increased the average of germination percentage by 65.83% and seed growth rate about 3.295% but could not increase plant height, leaf number, final wet weight, final dry weight dan relative growth rate. The combination of planting media  + compost increased the germination percentage by 73.33% and the seed growth about 3.40%, but not yet able to increase plant height, leaf number, final wet weight, final dry weight and relative growth rate of laban plant. This research is very important in preparing ready-to-plant seedlings in V. pinnata cultivation.

Sign in / Sign up

Export Citation Format

Share Document