Simulated frosting of tropical grasses

1974 ◽  
Vol 25 (1) ◽  
pp. 45 ◽  
Author(s):  
JB Hacker ◽  
BJ Forde ◽  
JM Gow
Keyword(s):  
Vapour Pressure Deficit ◽  
Frost Tolerance ◽  
Leaf Damage ◽  
Soluble Carbohydrates ◽  
Leaf Surfaces ◽  
Ranking Order ◽  
Simulated Field ◽  
Frost Period ◽  
Relationship Of ◽  
Tropical Grass

Ranking order for leaf damage was determined in six varieties of the tropical grass setaria after frosting in a controlled environment and was found to be similar to known field response. A frost temperature of –2.5°C provided good discrimination between populations subjected to three successive frost cycles of 4 hr under programmed conditions which closely simulated field conditions. Further experiments were carried out to investigate: (a) The relative frost tolerance of a range of varieties in the genera Setaria, Digitaria, Paspalum, and Lolium; (b) the effect of vapour pressure deficit (VPD) during frosting and rate of temperature change into the frost period on leaf damage; (c) the effect of temperatures preceding frosting and duration of frost on leaf damage; (d) the relationship of concentration of alcohol-soluble carbohydrates to susceptibility to frost. The most tolerant tropical grass tested was Paspalum dilatatum. Significant variation in frost tolerance in Setaria was related to altitude of origin, whereas in Paspalum plicatulum latitude of origin appeared to be the controlling factor. Frost tolerance was slightly increased by pre-hardening for 3 days or by growing at a lower night temperature. Frosting at a VPD of –3 mb resulted in less damage than frosting at a VPD of zero, when visible frost formed on leaf surfaces. Extending the duration of the frost resulted in an increase in leaf damage. Ranking order for frost tolerance was not attributable to differences in concentration of alcohol soluble carbohydrates and was not affected by environmental conditions either preceding or during the frost period.

Soybean seed coat cup unloading on plants with low-raffinose, low-stachyose seeds

2009 ◽  
Vol 19 (3) ◽  
pp. 145-153 ◽  
Author(s):  
Suzanne M. Kosina ◽  
Alexander Castillo ◽  
Steven R. Schnebly ◽  
Ralph L. Obendorf
Keyword(s):  
Seed Coat ◽  
Soybean Seed ◽  
Soluble Carbohydrates ◽  
Growth Stages ◽  
In Planta ◽  
Plant Growth Stages ◽  
Soybean Plants ◽  
Soybean Seed Coat ◽  
Relationship Of ◽  
The Relationship

AbstractSucrose, raffinose and stachyose accumulate in soybean [Glycine max L. (Merrill)] embryos during seed maturation. To determine the relationship of plant maternal composition on seed composition, soluble carbohydrates in three 1-cm2 leaf punches at three plant growth stages (R2, R3, R6) and in seed coat cup exudates in planta were analysed at four 30-min intervals on soybean plants (R5) with low-raffinose, low-stachyose (LRS) seeds expressing the mutant stc1 phenotype; low-raffinose, low-stachyose and low-phytin (LRSP1, LRSP2) seeds expressing the mutant mips phenotype; or normal raffinose, stachyose and phytin (CHECK) seeds expressing the Stc1 and Mips phenotype. Leaf sucrose (23.6 μg cm− 2), myo-inositol (9.3 μg cm− 2), d-chiro-inositol (6.7 μg cm− 2), d-ononitol (0.76 μg cm− 2), d-pinitol (50.1 μg cm− 2) and total soluble carbohydrates (107.1 μg cm− 2) were not significantly different between phenotypes. d-chiro-Inositol, myo-inositol, d-pinitol and sucrose were unloaded from soybean seed coat cups in planta at decreasing rates over the four sequential periods of sampling. Unloading rates of sucrose and myo-inositol were highest for LRS, d-pinitol was highest for LRSP2, and d-chiro-inositol was not different between LRS, LRSP1, LRSP2 and CHECK. Free cyclitols were 60% of total soluble carbohydrates in leaves and 20% in seed coat cup exudates. Except for sucrose and d-pinitol, seed phenotype had little influence on the composition of compounds unloaded from seed coats to maturing embryos of low-raffinose, low-stachyose seeds. Maternally supplied cyclitols may contribute, in part, to changes in the composition of cyclitol galactosides stored in mature seeds.

Characteristics of stomatal diffusion resistance in a Douglas fir forest exposed to soil water deficits

1977 ◽  
Vol 7 (4) ◽  
pp. 595-604 ◽  
Author(s):  
C. S. Tan ◽  
T. A. Black ◽  
J. U. Nnyamah
Keyword(s):  
Soil Water ◽  
Soil Water Potential ◽  
High Stress ◽  
Vapour Pressure Deficit ◽  
Douglas Fir ◽  
Diffusion Resistance ◽  
Total Water ◽  
Pressure Potential ◽  
Relationship Of ◽  
The Relationship

As part of a 2-year study of the effect of thinning on evapotranspiration in Douglas fir (Pseudotsugamenziesii (Mirb.) Franco), the relationship between stomatal diffusion resistance (rs) and environmental variables were studied. Research was conducted in an unthinned stand (1840 stems ha−1) with negligible undergrowth and a thinned stand (840 stems ha−1) with substantial salal (Gaultheriashallon Pursh) undergrowth. During the daytime rs was mainly related to the soil water potential (ψs) and the vapour pressure deficit (v.p.d.) of the canopy air. Daytime values of rs for Douglas fir ranged from 2 to 60 s cm−1 for values of v.p.d. between 4 and 24 mb (4 and 24 × 102 Pa) and values of ψs between 0 and −12.5 bars (0 and −12.5 × 105 Pa). Although increasing rs was usually associated with decreasing pressure potential of the twig xylem (ψt), increasing rs appeared to be associated with increasing ψt when the v.p.d. was high. Stress history was found to cause a shift in the relationship of rs to ψt, but had little effect on the relationship of rs to v.p.d. and ψs. Daytime values of rs for salal ranged from 2 to 45 s cm−1. This stomatal behaviour suggests that as the soil dried out, salal transpiration accounted for an increasing fraction of the total water loss by the thinned stand.

scholarly journals Insect folivory in Didymopanax vinosum (Apiaceae) in a vegetation mosaic of Brazilian cerrado

2006 ◽  
Vol 66 (2b) ◽  
pp. 671-680 ◽  
Author(s):  
E. M. Varanda ◽  
M. P. Pais
Keyword(s):  
Decisive Role ◽  
Sensu Stricto ◽  
Leaf Damage ◽  
Leaf Toughness ◽  
Scattered Trees ◽  
Insect Activity ◽  
Observed Damage ◽  
Relationship Of ◽  
Plant Apparency ◽  
The Relationship

Susceptibility of Didymopanax vinosum (Apiaceae) to insect herbivores was investigated in three sites of a cerrado mosaic - composed of campo cerrado (a grassland with scattered trees and shrubs), cerradão (a tall woodland) and cerrado sensu stricto (intermediate between the two) - situated in Cerrado Pé-de-Gigante, Santa Rita do Passa Quatro, SP, Brazil. We also examined the relationship of folivory with the composition and abundance of the insect herbivore fauna, and with several nutritional and defensive plant characteristics (water, nitrogen, cellulose, lignin, tannin leaf contents, and leaf toughness). We collected insects associated with D. vinosum every month, and we measured leaf damage every three months. In general, the annual folivory differed among sites. It reached the highest rates in site 1 and site 3: 7.33 and 8.5 percent, respectively. Only 1.32 percent of annual folivory was observed in site 2. These levels resulted from the higher abundance, in sites 1 and 3, of the thrips Liothrips didymopanacis (Phlaeothripidae), the most abundant herbivore sampled, responsible for more than 90 percent of the observed damage. However, no significant relationship was found between insect activity and the chemical and physical composition of the leaves. Our findings suggest that, at least in this species, other chemical compounds or variables related to plant apparency and resource availability to herbivores (e.g. plant architecture) might play a more decisive role in the spatial variation of folivory than the nutritional and defensive traits that were analyzed.

Screening eucalypts for frost tolerance in breeding programs

1992 ◽  
Vol 22 (9) ◽  
pp. 1271-1277 ◽  
Author(s):  
C.A. Raymond ◽  
J.V. Owen ◽  
K.G. Eldridge ◽  
C.E. Harwood
Keyword(s):  
Data Analysis ◽  
Genetic Selection ◽  
Leaf Tissue ◽  
Frost Tolerance ◽  
Leaf Damage ◽  
Alternative Methods ◽  
Small Samples ◽  
Leaf Discs ◽  
Relative Conductivity ◽  
Highly Correlated

Improvements in a laboratory technique and statistical methods for screening eucalypts for relative frost tolerance using small samples of leaf tissue are described. As a contribution to more efficient genetic selection in a breeding program, these methods aim to provide reliable estimates of relative frost tolerance for ranking genotypes and to allow partitioning of total variation into components due to provenances, families, and individuals. Examination of sampling strategies indicated that four leaf discs per seedling at three frosting temperatures and 10 seedlings per family provided highly reliable estimates of frost tolerance. Mean relative conductivity values were found to be highly correlated with mean leaf damage sustained by a seedling across the whole range of values. Alternative methods of data analysis are compared. Estimation of LD50 values (the temperature at which 50% of leaf discs would be killed) and calculation of percent survival of leaf discs were found to be less efficient means of data analysis than directly analysing relative conductivity values. The nature of genetic control of frost tolerance and the assumptions underlying such nondestructive screening techniques are examined.

Seasonal changes in water-soluble carbohydrates of Populus tremuloides leaves

1981 ◽  
Vol 59 (5) ◽  
pp. 862-869 ◽  
Author(s):  
H. G. Wildman ◽  
D. Parkinson
Keyword(s):  
Populus Tremuloides ◽  
Seasonal Changes ◽  
Tree Canopy ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Leaf Leachate ◽  
Leaf Surfaces ◽  
Microbial Development ◽  
Poplar Leaf ◽  
Sampling Times

Leaf leaching was simulated by washing leaves in distilled water. A variation in the quality and quantity of aspen poplar leaf leachate carbohydrates with respect to season and height in the tree canopy was observed. Some carbohydrates were subject to less variation than others. Fructose was the major component of the leachate carbohydrate at all sampling times. Other carbohydrates occurring in the leachate included glucose, galactose, inositol, sucrose, maltose, raffinose, an unknown 12-C, and an unknown 18-C carbohydrate. The possibility that restricted availability of total and (or) particular carbohydrates may play a role in controlling microbial development on leaf surfaces is discussed.

scholarly journals Drivers of immersive virtual reality adoption intention: a multi-group analysis in chemical industry settings

2021 ◽  
Author(s):  
Ryo Toyoda ◽  
Fernando Russo Abegão ◽  
Sue Gill ◽  
Jarka Glassey
Keyword(s):  
Work Experience ◽  
Structural Equation ◽  
Quantitative Research ◽  
Group Analysis ◽  
Online Questionnaire ◽  
Use Of Technology ◽  
Significant Difference ◽  
Ranking Order ◽  
Socio Demographic Factors ◽  
Relationship Of

AbstractThe present study uses the modified Unified Theory of Acceptance and Use of Technology 2 to examine the effect of factors such as performance expectancy (PE), effort expectancy (EE), social influence (SI), and hedonic motivation (HM) that may motivate operators and employees to adopt IVR-based technology into their training. Results of a multi-group analysis based on nationality, prior IVR experience, and/or length of work experience, to analyse the potential similarities and/or differences in perception and acceptance towards using IVR-based technology are also presented. The quantitative research data were gathered using an online questionnaire from 438 chemical operators and/or employees who either speak German, French, or English. Partial least squares structural equation modelling and multi-group analysis based on SmartPLS™ version 3 were used to carry out the path and multi-group analyses. The results show that the behavioural intention (BI) towards adoption of IVR was influenced by PE, EE, and HM for all abovementioned subpopulation. However, the relationship of SI to BI was not supported for respondents with prior IVR experience and for respondents coming from Western region. Although Henseler’s-based multi-group PLS analysis reveals that there was no significant difference between the group comparisons, it is still important to take into account these socio-demographic factors as there are definite group differences in terms of the ranking order of each construct for the IVR adoption intentions among each subpopulation. The implications and future directions were discussed.

scholarly journals Influence of Fertilizer Rregime on Leaf Chlorosis/Necrosis of Two Varieties of Chrysanthemum

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 763C-763
Author(s):  
Trinidad Reyes ◽  
Terril A. Nell ◽  
James E. Barrett
Keyword(s):  
Leaf Damage ◽  
Soluble Carbohydrates ◽  
Fertilizer Rate ◽  
Leaf Chlorosis ◽  
Carbohydrate Depletion ◽  
Soluble Fertilizer

`Tara' and `Boaldi' were fertilized with 150 and 450 ppm from 20N–4.7P–16.6K soluble fertilizer and moved at flowering to postproduction conditions (21 ± 2C and 10 μmol·m–2·s–1). Shipping was simulated for 1 week at 26C. `Tara' exhibited burned leaf margins (necrosis) and chlorosis following shipping. At 150 ppm, leaves had brown, dried margins, but the damage did not progress indoors. Necrosis was worse at 450 ppm. Leaf chlorosis/necrosis of non-shipped plants at the 450 fertilizer level did not appear until the 3rd week indoors. At experiment termination, no leaf damage occurred in non-shipped `Tara' or `Boaldi' with 150 ppm. `Boaldi' did not show damage after shipping regardless of the treatment but symptoms (necrosis and wilting of leaves) evolved during the first 2 weeks indoors on plants fertilized with 450 ppm. A 50% reduction in root soluble carbohydrates was found at the highest fertilizer rate at flowering, suggesting that leaf chlorosis/necrosis is related to carbohydrate depletion in chrysanthemum.

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