The tolerance of wheat to hight temperatures during reproductive growth. 2. Grain development

1989 ◽  
Vol 40 (1) ◽  
pp. 15 ◽  
Author(s):  
IF Wardlaw ◽  
IA Dawson ◽  
P Munibi
Keyword(s):  
Genetic Variation ◽  
High Temperature ◽  
Dry Weight ◽  
Grain Development ◽  
High Radiation ◽  
Grain Number ◽  
Temperature Conditions ◽  
Specific Source ◽  
Parental Lines ◽  
Low Sensitivity

A study was undertaken in the Canberra phytotron of the response of 66 cultivars of wheat to high temperature (30/25�C) imposed throughout the period of grain development. The results from 20 Australian cultivars and their parental lines showed half of these to be clustered in the range where grain dry weight was reduced by 30-35% in response to high temperature when compared with 18/13�C controls. The non-Australian lines were more normally distributed in their response to high temperature and included some cultivars that were less sensitive to high temperature than the best of the Australian lines. It was concluded that there is a need for a wider assessment of genetic variation if a response to high temperature is to be incorporated in a breeding programme. A more specific study on Kalyansona, one of the better cultivars under high temperature conditions and high radiation levels, failed to reveal a specific source of temperature insensitivity in the background of Kalyansona. A comparison of the response to high temperature during grain development of twoF1 hybrids with their parental lines (Banks, Kalyansona and Pinnacle) provided some evidence that traits such as high grain number per ear, large grains and low sensitivity to high temperature could be effectively combined to produce a high grain weight per ear under high temperature conditions.

The effects of copper and nitrogen supply on the distribution of copper in dissected wheat grains

1979 ◽  
Vol 30 (2) ◽  
pp. 233 ◽  
Author(s):  
J Hill ◽  
AD Robson ◽  
JF Loneragan
Keyword(s):  
Copper Concentration ◽  
Copper Deficiency ◽  
Dry Weight ◽  
Copper Level ◽  
Grain Development ◽  
Whole Grain ◽  
Potential Response ◽  
Grain Number ◽  
Poor Indicator ◽  
Individual Grains

The distribution of copper between the embryo and the endosperm was studied in the grain of two wheat cultivars (Gamenya and Petit Rojo) grown at marginal and sufficient copper and two levels of nitrogen. Copper concentration in whole grain increased markedly with copper level but differed little with nitrogen level. The dry weight and copper content of the embryo expressed as a proportion of the whole grain varied little among treatments, so that copper concentration in the embryo responded to treatment in a similar way to copper concentration in the whole grain. Copper concentrations in the embryo were at least 2.5 times as high as in the endosperm or whole grain at all levels of copper and nitrogen. It is suggested that where copper deficiency decreases grain number without decreasing the weight of individual grains the copper concentration in the mature whole grain, or in the embryo, is not causally related to grain development, and may be a poor indicator of the potential response of grain yield to copper application.

Factors Limiting the Rate of Dry Matter Accumulation in the Grain of Wheat Grown at High Temperature

1980 ◽  
Vol 7 (4) ◽  
pp. 387 ◽  
Author(s):  
IF Wardlaw ◽  
I Sofield ◽  
PM Cartwright
Keyword(s):  
High Temperature ◽  
Temperature Increase ◽  
Dry Matter ◽  
Flag Leaf ◽  
Dry Weight ◽  
Dry Matter Accumulation ◽  
Grain Development ◽  
Temperature Ranges ◽  
Higher Temperature ◽  
Lower Temperature

Increasing temperatures from 21/16°C to 30/25°C, during the period of development from anthesis to maturity, substantially reduced grain dry weight in wheat. Although this was associated with a shorter duration of grain development, the failure to obtain any compensating increase in the rate of dry matter accumulation, as occurs in the lower temperature ranges, was also considered important. There was no evidence that night temperatures were more important than day temperatures. Analysis of the movement of 14C-labelled photosynthate from the flag leaf to the ear indicated a faster rate of import of photosynthate by the grain at the higher temperature. However carbon lost through respiration is a component of the ear demand for photosynthate and it appears that increase in movement of photosynthate was balanced by greater respiratory losses. This additional carbon lost through enhanced respiration at high temperature could, however, only account at the most for 25% of the reduction in grain dry weight that occurred with the temperature increase from 21/16°C to 30/25°C. Altering either the demand for photosynthate by grain removal, or the supply of photosynthate by a defoliation and shading treatment, did not prevent the reduction in grain dry weight due to high temperature and this is a further indication that the temperature effect occurred mainly within, or close to, the grain itself, and did not result from an effect on the availability of photosynthate.

Genetic variation for rate of establishment in caucasian clover

1998 ◽  
pp. 213-217
Author(s):  
K.H. Widdup ◽  
T.L. Knight ◽  
C.J. Waters
Keyword(s):  
Genetic Variation ◽  
Root Growth ◽  
Seedling Growth ◽  
White Clover ◽  
Seedling Emergence ◽  
Red Clover ◽  
Dry Weight ◽  
Cool Season ◽  
Trifolium Ambiguum ◽  
Root Dry Weight

Slow establishment of caucasian clover (Trifolium ambiguum L.) is hindering the use of this legume in pasture mixtures. Improved genetic material is one strategy of correcting the problem. Newly harvested seed of hexaploid caucasian clover germplasm covering a range of origins, together with white and red clover and lucerne, were sown in 1 m rows in a Wakanui soil at Lincoln in November 1995. After 21 days, the caucasian clover material as a group had similar numbers of emerged seedlings as white clover and lucerne, but was inferior to red clover. There was wide variation among caucasian clover lines (48-70% seedling emergence), with the cool-season selection from cv. Monaro ranked the highest. Recurrent selection at low temperatures could be used to select material with improved rates of seedling emergence. Red clover and lucerne seedlings produced significantly greater shoot and root dry weight than caucasian and white clover seedlings. Initially, caucasian clover seedlings partitioned 1:1 shoot to root dry weight compared with 3:1 for white clover. After 2 months, caucasian clover seedlings had similar shoot growth but 3 times the root growth of white clover. Between 2 and 5 months, caucasian clover partitioned more to root and rhizome growth, resulting in a 0.3:1 shoot:root ratio compared with 2:1 for white clover. Both clover species had similar total dry weight after 5 months. Unhindered root/ rhizome devel-opment is very important to hasten the establishment phase of caucasian clover. The caucasian clover lines KZ3 and cool-season, both selections from Monaro, developed seedlings with greater shoot and root growth than cv. Monaro. KZ3 continued to produce greater root growth after 5 months, indicating the genetic potential for improvement in seedling growth rate. Different pasture estab-lishment techniques are proposed that take account of the seedling growth characteristics of caucasian clover. Keywords: establishment, genetic variation, growth, seedling emergence, Trifolium ambiguum

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

scholarly journals GERMINATION AND VIGOUR IN SEEDS OF THE COWPEA IN RESPONSE TO SALT AND HEAT STRESS

2019 ◽  
Vol 32 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Luma Rayane de Lima Nunes ◽  
Paloma Rayane Pinheiro ◽  
Charles Lobo Pinheiro ◽  
Kelly Andressa Peres Lima ◽  
Alek Sandro Dutra
Keyword(s):  
Salt Stress ◽  
Heat Stress ◽  
High Temperature ◽  
Low Temperature ◽  
Vigna Unguiculata ◽  
Salt Concentration ◽  
Dry Weight ◽  
Germination Percentage ◽  
Different Types ◽  
Different Temperatures

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.

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