scholarly journals Protocorm mycobionts of the Federally threatened eastern prairie fringed orchid, Platanthera leucophaea (Nutt.) Lindley, and a technique to prompt leaf elongation in seedlings

2005 ◽  
Vol 53 ◽  
pp. 163-171 ◽  
Author(s):  
Lawrence W. Zettler ◽  
Kurt A. Piskin ◽  
Scott L. Stewart ◽  
Jared J. Hartsock ◽  
Marlin L. Bowles ◽  
...  
2001 ◽  
Vol 19 (4) ◽  
pp. 235-241 ◽  
Author(s):  
Marlin Bowles ◽  
Jenny McBride ◽  
Timothy Bell
Keyword(s):  

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 134
Author(s):  
Sabine Stuerz ◽  
Folkard Asch

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.


2013 ◽  
Vol 85 (1) ◽  
pp. 371-377 ◽  
Author(s):  
Marcos F Silva ◽  
Edson M. V Porto ◽  
Dorismar D Alves ◽  
Cláudio M.T Vitor ◽  
Ignacio Aspiazú

This study aims to evaluate the morphogenetic characteristics of three cultivars of Brachiaria brizantha subjected to nitrogen fertilization. The design was a randomized block in factorial arrangement 4x3; three cultivars of B. brizantha - Marandu, Piatã, Xaraés and four nitrogen levels - 0, 80, 160 and 240 kg/ha, with three replications. The experimental units consisted of plastic pots filled with 5 dm3 of soil. Thereupon the establishment fertilization, varieties were sowed directly in the pots, leaving, after thinning, five plants per pot. Forty-five days after planting, it was done a standardization cut at 10 cm tall. Nitrogen levels were distributed according to the treatments, divided in three applications. The morphogenetic characteristics were evaluated in three tillers per sampling unit and data were submitted to analysis of variance and regression. For all evaluated characteristics there was no interaction between factors cultivar and nitrogen levels, verifying only the effects of nitrogen on the variables leaf appearance rate and phyllochron. The dose 240 kg/ha of N corresponds to the greater leaf appearance rate. Cultivar Marandu shows the higher leaf blade: pseudostem and ratio of leaf elongation rate and elongation pseudostem, which favors higher forage quality.


2018 ◽  
Vol 33 (9) ◽  
pp. 1645-1646
Author(s):  
Javan M. Bauder ◽  
David R. Breininger ◽  
M. Rebecca Bolt ◽  
Michael L. Legare ◽  
Christopher L. Jenkins ◽  
...  

2018 ◽  
Vol 17 (1) ◽  
pp. 63
Author(s):  
ANDRIELI HEDLUND BANDEIRA ◽  
SANDRO LUIS PETTER MEDEIROS ◽  
BEATRIZ MARTI EMYGDIO ◽  
JEAN CECCHIM BIONDO ◽  
LINEU TRINDADE LEAL

RESUMO - O objetivo deste trabalho foi avaliar as características morfogênicas do colmo principal de genótipos de sorgo sacarino, em diferentes espaçamentos entrelinhas e épocas de semeadura. O experimento foi conduzido em Santa Maria-RS, em delineamento experimental de blocos ao acaso em esquema trifatorial (2x2x3), com dois genótipos de sorgo sacarino (BRS 506 e Fepagro 19), dois espaçamentos entrelinhas (0,50 m e 0,70 m) e três épocas de semeadura (outubro, novembro e dezembro), quatro repetições e dois anos de cultivo. Foram avaliadas a taxa de alongamento das folhas, o número final de folhas no colmo, a taxa de surgimento de folha, filocrono e taxa de elongamento de colmo. As variáveis não apresentaram interação tripla significativa entre genótipo, espaçamento de entrelinhas e época de semeadura. O genótipo BRS 506 apresentou número de folhas acumuladas, taxa de alongamento de folhas nas épocas de semeaduras constante. O atraso na época de semeadura resulta em menor número de folhas acumuladas e taxa de elongação do colmo para o Fepagro 19. O filocrono para o espaçamento entrelinhas 0,70 m é inferior ao de 0,50 m. Os genótipos estudados estão aptos para a produção na região, desde que a semeadura ocorra no mês de outubro. Palavras-chave: alongamento foliar, filocrono, graus-dia, índice Haun, Sorghum bicolor. LEAF MORPHOLOGY OF SWEET SORGHUM CULTIVATED IN DIFFERENT ROW SPACINGS AND SOWING DATES ABSTRACT - The objective of this work was to evaluate the morphogenic characteristics of the main stem of sweet sorghum genotypes in different spacing between lines and sowing times. The experimental was carried out in a randomized complete block design in a trifactorial scheme (2x2x3), with two sweet sorghum (BRS 506 and Fepagro 19), two spacing between lines (0.50 m and 0.70 m) and three sowing seasons (October, November and December), four replications and two years of cultivation. The leaf elongation rate, the final number of leaves in the stem, the leaf appearance rate, phyllochron and shoot elongation rate were evaluated. The variables did not present significant triple interaction between genotype, spacing between rows and sowing time. The genotype BRS 506 presented a number of accumulated leaves, leaf elongation rate at constant sowing times. The delay in sowing seasons results in a lower number of accumulated leaves and the elongation rate of the stem for genotype Fepagro 19. The phyllochron for the 0.70 m line spacing is less than 0.50 m. The genotypes studied are suitable for production in the region, as long as sowing occurs in October.Keywords: leaf elongation, phyllochron, degree-days, Haun index, Sorghum bicolor.


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