Thermal Adaptation of Pennisetum: Seedling Development

1975 ◽  
Vol 2 (3) ◽  
pp. 413 ◽  
Author(s):  
CJ Pearson
Keyword(s):  
Leaf Development ◽  
Seedling Survival ◽  
Thermal Adaptation ◽  
Dry Weight ◽  
Early Growth ◽  
Seedling Development ◽  
Leaf Area Expansion ◽  
Specific Hybrid ◽  
Seedling Germination ◽  
Area Expansion

Germination, establishment, dry weight accumulation and leaf development of seedlings of two Pennisetum typhoides cultivars and a P. typhoides × P. purpureum biotype were studied at four temperatures from 33/28 to 15/10°C (day/night) under natural irradiances. Percentage seedling germination was independent of temperature. However, rate of germination and emergence were fastest, the spread in populations of time to germination least, and seedling survival highest, at the temperature at which rates of leaf area expansion and dry weight accumulation were greatest, i.e. 33/28°C. Rates of dry weight accumulation differed between the three pennisetums, the ranking in early growth at temperatures below 33/28°C being the same as that for seed size, and in later growth at all temperatures being in the order interspecific hybrid > intra-specific hybrid > selected strain.

EFFECTS OF TEMPERATURE ON PRIMARY GROWTH AND REGROWTHS OF ALFALFA

1972 ◽  
Vol 52 (6) ◽  
pp. 1017-1027 ◽  
Author(s):  
C. J. PEARSON ◽  
L. A. HUNT
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Dry Weight ◽  
Growth Responses ◽  
Primary Growth ◽  
Whole Plant ◽  
Leaf Area Expansion ◽  
Medicago Sativa L ◽  
Effects Of Temperature ◽  
Area Expansion

The cumulative gain and distribution of dry matter are described for both primary growth and three subsequent regrowths of alfalfa (Medicago sativa L.) cults Vernal and Moapa at an irradiance (400–700 nm) of 25 nE cm−2 s−1 and day/night temperatures of 20/15 C and 30/25 C. Whole plant dry weight and leaf areas increased curvilinearly with time in primary growth and linearly in regrowth. Root plus stubble weight after cutting, increased from first to third regrowth. Rates of leaf area expansion increased with time in primary growth but were constant in regrowth; they were higher in regrowth than in primary growth, and higher at 20/15 C than at 30/25 C. Individual leaf area was greater at 20/15 C than at 30/25 C, whereas average specific leaf weight was less at 20/15 C than at 30/25 C. This latter finding probably reflected longer leaf life at 20/15 C. Number of days to 50% flowering was greater at 20/15 C than at 30/25 C. Growth responses to temperature were similar during primary growth and regrowths.

scholarly journals Influência da profundidade e posição de semeadura na emergência de Acacia polyphylla DC.

2016 ◽  
Vol 11 (1) ◽  
pp. 23 ◽  
Author(s):  
A. J. Rodrigues ◽  
E. M. C. Batista ◽  
L. M. Oliveira ◽  
A. C. F. Portella ◽  
P. B. Souza
Keyword(s):  
Secondary Succession ◽  
Dry Weight ◽  
Early Growth ◽  
Seedling Development ◽  
Medium Size ◽  
Horizontal Position ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Growth Of Seedlings ◽  
The Ideal

<p>A<em> Acacia polyphylla </em>DC.<em> </em>é uma leguminosa, pertencente à família Fabaceae, conhecida principalmente por monjoleiro, cuja árvore apresenta porte médio e rápido crescimento, a mesma enquadra-se em estágios iniciais da sucessão secundária com grande potencial para o uso na recuperação de áreas degradadas do Bioma Cerrado. Assim, objetivou-se avaliar a influência de diferentes posições e de profundidades de semeadura na emergência e crescimento inicial de plântulas de <em>Acacia polyphylla </em>DC. O experimento foi realizado em delineamento inteiramente casualisado, com quatro repetições de 25 sementes, dispostos em esquema fatorial 3 x 5 (posições e profundidades de semeadura). Os tratamentos consistiram em diferentes posições das sementes no substrato: hilo voltado para cima, hilo voltado para baixo e sementes na horizontal, nas profundidades de 1, 2, 3, 4 e 5 cm. Determinou-se a porcentagem de emergência, índice de velocidade de emergência, bem como o comprimento e a massa seca da parte aérea e da raiz das plântulas. A emergência e o crescimento inicial das plântulas de <em>Acacia polyphylla </em>DC<em> </em>são afetadas pelas posições e profundidades de semeaduras, sendo que o procedimento ideal para o plantio e desenvolvimento das plântulas deve ser em uma profundidade entre 1,4 e 2,8 cm com o hilo na posição horizontal.</p><p align="center"><strong><em>Influence of depth and sowing position in the emergency Acacia polyphylla DC.</em></strong></p><p><strong>Abstract</strong><strong>: </strong><em>Acacia polyphylla</em> DC. is a legume belonging to the Fabaceae family, mainly known for monjoleiro whose tree has medium size and rapid growth, it fits in the early stages of secondary succession with great potential for use in the recovery of degraded areas of the Cerrado Biome. The objective was to evaluate the influence of different positions and sowing depths in the emergence and early growth of seedlings <em>Acacia polyphylla</em> DC. The experiment was conducted in completely randomized design with four replications of 25 seeds, arranged in a factorial 3 x 5 (positions and sowing depths). The treatments consisted of different positions of the seeds in the substrate: hilum facing up, hilum facing down and seeds horizontally at depths of 1, 2, 3, 4 and 5 cm. It was determined the percentage of emergence, emergence speed index, as well as the length and dry weight of shoot and root of seedlings. The emergence and early growth of seedlings <em>Acacia polyphylla</em> DC. are affected by the positions and sowing depths, and the ideal procedure for planting and seedling development must be at a depth between 1.4 and 2.8 cm, with the hilum in horizontal position.</p>

scholarly journals Substrate in the emergence and initial growth of seedlings of Caesalpinia pulcherrima

2017 ◽  
Vol 47 (3) ◽  
Author(s):  
Magnólia Martins Alves ◽  
◽  
Edna Ursulino Alves ◽  
Luciana Rodrigues de Araújo ◽  
Maria de Lourdes dos Santos Lima ◽  
...  
Keyword(s):  
Rice Straw ◽  
Urban Forestry ◽  
Dry Weight ◽  
Early Growth ◽  
Seedling Development ◽  
Wood Dust ◽  
Initial Growth ◽  
Saw Dust ◽  
Vegetable Soil ◽  
Growth Of Seedlings

ABSTRACT: Caesalpinia pulcherrima is an exotic species belongs to the Fabaceae family commonly known as flamboyant-mirim, and widely used for urban forestry. This study aimed to evaluate the effect of different substrates on the emergence and early seedlings growth of C. pulcherrima . The experiment was conducted in a greenhouse belonging to the Centro de Ciências Agrárias, Universidade Federal da Paraíba. The experimental design was completely randomized and treatments had 14 substrates: sand, vegetable soil, vermiculite, wood dust, carbonized rice straw, vegetable soil + sand 1:1, sand + wood dust 1:1, sand + carbonized rice straw 1:1, earth + wood dust 1:1, vegetable soil + carbonized rice straw 1:1, vermiculite + sand 1:1, vermiculite + wood dust 1:1, vermiculite + earth 1:1 and vermiculite + carbonized rice straw 1:1. Evaluation of the effect of the treatments was through the following determinations: percentage of emergency, first count, index of germination speed, length and dry weight of roots and shoots. The vermiculite, vegetable soil + sand 1:1, vermiculite + sand 1:1, vermiculite + saw dust 1:1, are suitable for emergence and early growth of seedlings of Caesalpinia pulcherrima . Substrates saw dust and carbonized rice straw were responsible for the worst performers on emergence and seedling development.

scholarly journals Responses of Rice Growth to Day and Night Temperature and Relative Air Humidity—Leaf Elongation and Assimilation

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 134
Author(s):  
Sabine Stuerz ◽  
Folkard Asch
Keyword(s):  
Leaf Area ◽  
Leaf Growth ◽  
Crop Growth ◽  
Air Humidity ◽  
Leaf Elongation ◽  
Night Temperature ◽  
Relative Air Humidity ◽  
Leaf Area Expansion ◽  
Plant Level ◽  
Area Expansion

Predictions of future crop growth and yield under a changing climate require a precise knowledge of plant responses to their environment. Since leaf growth increases the photosynthesizing area of the plant, it occupies a central position during the vegetative phase. Rice is cultivated in diverse ecological zones largely differing in temperature and relative air humidity (RH). To investigate the effects of temperature and RH during day and night on leaf growth, one variety (IR64) was grown in a growth chamber using 9 day/night regimes around the same mean temperature and RH, which were combinations of 3 temperature treatments (30/20 °C, 25/25 °C, 20/30 °C day/night temperature) and 3 RH treatments (40/90%, 65/65%, 90/40% day/night RH). Day/night leaf elongation rates (LER) were measured and compared to leaf gas exchange measurements and leaf area expansion on the plant level. While daytime LER was mainly temperature-dependent, nighttime LER was equally affected by temperature and RH and closely correlated with leaf area expansion at the plant level. We hypothesize that the same parameters increasing LER during the night also enhance leaf area expansion via shifts in partitioning to larger and thinner leaves. Further, base temperatures estimated from LERs varied with RH, emphasizing the need to take RH into consideration when modeling crop growth in response to temperature.

scholarly journals Accelerating Seed Germination and Juvenile Growth of Sorghum (Sorghum bicolor L. Moench) to Manage Climate Variability through Hydro-Priming

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 419
Author(s):  
Siaka Dembélé ◽  
Robert B. Zougmoré ◽  
Adama Coulibaly ◽  
John P. A. Lamers ◽  
Jonathan P. Tetteh
Keyword(s):  
Seed Germination ◽  
Climate Variability ◽  
Germination Rate ◽  
Dry Weight ◽  
Seed Priming ◽  
Seedling Development ◽  
Hot Water ◽  
Crop Failure ◽  
Simple Method ◽  
Early Season

Agriculture in Mali, a country in Sahelian West Africa, strongly depends on rainfall and concurrently has a low adaptive capacity, making it consequently one of the most vulnerable regions to climate change worldwide. Since early-season drought limits crop germination, and hence growth, ultimately yield during rain-fed depending on production is commonly experienced nowadays in Mali. Germination and establishment of key crops such as the staple sorghum could be improved by seed priming. The effects of hydro-priming with different water sources (e.g., distilled, tap, rain, river, well water) were evaluated respectively for three priming time durations in tepid e.g., at 25 °C (4, 8, and 12 h) and by hot water at 70 °C (in contrast to 10, 20, and 30 min.) in 2014 and 2015. Seed germination and seedling development of nine sorghum genotypes were monitored. Compared to non-primed seed treatments, hydro-priming significantly [p = 0.01] improved final germination percentage, germination rate index, total seedling length, root length, root vigor index, shoot length, and seedling dry weight. The priming with water from wells and rivers resulted in significant higher seed germination (85%) and seedling development, compared to the three other sources of water. Seed germination rate, uniformity, and speed were enhanced by hydro-priming also. It is argued that hydro-priming is a safe and simple method that effectively improve seed germination and seedling development of sorghum. If used in crop fields, the above most promising genotypes may contribute to managing early season drought and avoid failure of seed germination and crop failure in high climate variability contexts.

Bigleaf maple seedling establishment and early growth in Douglas-fir forests

1988 ◽  
Vol 18 (10) ◽  
pp. 1226-1233 ◽  
Author(s):  
Jeremy S. Fried ◽  
John C. Tappeiner II ◽  
David E. Hibbs
Keyword(s):  
Seed Predation ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Early Growth ◽  
Douglas Fir ◽  
Stand Development ◽  
Size Distributions ◽  
Canopy Density ◽  
Successful Establishment ◽  
Survival Of Seedlings

Survival, age and height distributions, and stocking of bigleaf maple (Acermacrophyllum Pursh) seedlings were studied in 1- to 250-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands in western Oregon to identify the stages in stand development in which bigleaf maple is most likely to establish successfully from seed. Maple seedling emergence averaged 30–40% where seeds were planted and protected from rodents but was typically <2% for unprotected seeds. Seedling survival after 2 years was highly dependent on canopy density, measured by percent sky. Average 1st-year survival of seedlings originating from planted, protected seeds was highest in clearcuts (1–2 years old, 36% survival, 56% sky) and pole-size stands (41–80 years old, 30% survival, 17% sky) with sparse understories and canopies. It was lowest in young stands with dense canopies (20–40 years old, 4% survival, 8% sky) and old stands (81–250 years old, 14% survival, 13% sky) with dense understories. Naturally regenerated populations of bigleaf maple seedlings, which occurred in aggregations (0.005–0.04 ha in area), were most abundant (up to 10 000/ha) in pole-size Douglas-fir stands. Although seedling size distributions within stands had a strongly inverse J shaped form, size distributions within aggregations appeared more normal (bell-shaped). Seedling age rarely exceeded 15 years. Seedlings grew slowly in the understory, often reaching only 25 cm in height after 8–10 years, and were intensively browsed by deer. Naturally regenerated seedlings were virtually absent from clearcuts, probably because of dense competing vegetation and lack of seed caused by poor dispersal and seed predation. The "window" for the most successful establishment of bigleaf maple seedlings appears to begin after canopy thinning and end before forbs and shrubs invade.

scholarly journals Seedling Developmental Stage at Transplanting Affects Growth and Flowering of Medallion Flower and Globe Amaranth

2015 ◽  
Vol 33 (2) ◽  
pp. 53-57 ◽  
Author(s):  
G.J. Keever ◽  
J.R. Kessler ◽  
G.B. Fain ◽  
D.C. Mitchell
Keyword(s):  
Shoot Growth ◽  
Growth Index ◽  
Dry Weight ◽  
Development Stage ◽  
Seedling Development ◽  
Bedding Plants ◽  
Shoot Dry Weight ◽  
Flower Growth ◽  
Root Restriction ◽  
Experimental Runs

A study was conducted to determine how seedling development stage at transplanting from plug flats into small pots affected growth and flowering of two commonly grown bedding plants. Seeds of Showstar® medallion flower and ‘Las Vegas Pink’ globe amaranth were sown in 392-cell flats on five dates for each of two experimental runs before transplanting into 8.9 cm (3.5 in) cubic pots. At transplanting of both species, plant height, node count and shoot dry weight increased as days from sowing to transplanting increased and there was no visible cessation in shoot growth due to root restriction. Time to first flower from transplanting decreased linearly with both species in both runs, except with medallion flower in the second run, as time from sowing to transplanting increased. In contrast, time to flower of both species from sowing increased linearly as time from sowing to transplanting increased. However, the magnitude of the increase or decrease in time to flower differed between the two runs indicating that other factors, most likely light intensity and duration, besides node counts were affecting time to flower. Globe amaranth height and growth index and medallion flower growth index at first flower decreased as time from sowing to transplanting increased, whereas medallion flower height was not affected by time from sowing to transplanting.

scholarly journals Acclimation of Photosynthetic Activity of Zantedeschia `Best Gold' in Response to Temperature and Photosynthetic Photon Flux

2002 ◽  
Vol 127 (2) ◽  
pp. 290-296 ◽  
Author(s):  
Keith A. Funnell ◽  
Errol W. Hewett ◽  
Julie A. Plummer ◽  
Ian J. Warrington
Keyword(s):  
Quantum Yield ◽  
Leaf Area ◽  
Photosynthetic Rate ◽  
Photosynthetic Activity ◽  
Natural Habitat ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Leaf Area Expansion ◽  
Response To Temperature ◽  
Area Expansion

Photosynthetic activity of individual leaves of Zantedeschia Spreng. `Best Gold' aff. Z. pentlandii (Wats.) Wittm. [syn. Richardia pentlandii Wats.] (`Best Gold'), were quantified with leaf expansion and diurnally, under a range of temperature and photosynthetic photon flux (PPF) regimes. Predictive models incorporating PPF, day temperature, and percentage leaf area expansion accounted for 78% and 81% of variation in net photosynthetic rate (Pn) before, and postattainment of, 75% maximum leaf area, respectively. Minimal changes in Pn occurred during the photoperiod when environmental conditions were stable. Maximum Pn (10.9μmol·m-2·s-1 or 13.3 μmol·g-1·s-1) occurred for plants grown under high PPF (694 μmol·m-2·s-1) and day temperature (28 °C). Acclimation of Pn was less than complete, with any gain through a greater light-saturated photosynthetic rate (Pmax) at high PPF also resulting in a reduction in quantum yield. Similarly, any gain in acclimation through increased quantum yield under low PPF occurred concurrently with reduced Pmax. It was concluded that Zantedeschia `Best Gold' is a shade tolerant selection, adapted to optimize photosynthetic rate under the climate of its natural habitat, by not having obligate adaptation to sun or shade habitats.

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