scholarly journals Growth Rates of Lymantria dispar Larvae and Quercus robur Seedlings at Elevated CO2 Concentration and Phytophthora plurivora Infection

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1059
Author(s):  
Slobodan Milanović ◽  
Ivan Milenković ◽  
Jovan Dobrosavljević ◽  
Marija Popović ◽  
Alejandro Solla ◽  
...  

Interactions between plants, insects and pathogens are complex and not sufficiently understood in the context of climate change. In this study, the impact of a root pathogen on a leaf-eating insect hosted by a tree species at elevated CO2 concentration is reported for the first time. The combined and isolated effects of CO2 and infection by the root pathogen Phytophthora plurivora on English oak (Quercus robur) seedlings were used to assess growth rates of plants and of gypsy moth (Lymantria dispar) larvae. For this purpose, two Q. robur provenances (Belgrade and Sombor) were used. At ambient CO2 concentration, the relative growth rates of larvae consuming leaves of plants infected by P. plurivora was higher than those consuming non-infected plants. However, at elevated CO2 concentration (1000 ppm) higher relative growth rates were detected in the larvae consuming the leaves of non-infected plants. At ambient CO2 concentration, lower growth rates were recorded in L. dispar larvae hosted in Q. robur from Belgrade in comparison to larvae hosted in Q. robur from Sombor. However, at elevated CO2 concentration, similar growth rates irrespective of the provenance were observed. Defoliation by the gypsy moth did not influence the growth of plants while P. plurivora infection significantly reduced tree height in seedlings from Belgrade. The results confirm that a rise of CO2 concentration in the atmosphere modifies the existing interactions between P. plurivora, Q. robur, and L. dispar. Moreover, the influence of the tree provenances on both herbivore and plant performance at elevated CO2 concentrations suggests a potential for increasing forest resilience through breeding.

1996 ◽  
Vol 26 (9) ◽  
pp. 1556-1568 ◽  
Author(s):  
Thimmappa S. Anekonda ◽  
Richard S. Criddle ◽  
Lee D. Hansen ◽  
Mike Bacca

Seventeen Eucalyptus species and 30 rapid-growing Eucalyptuscamaldulensis trees (referred to as plus trees), growing in a plantation were studied to examine relationships among measured plant growth and respiratory parameters, geographical origins, and growth climate. The respiratory parameters measured at two different temperatures by isothermal calorimetry were metabolic heat rate, rate of CO2 production, and the ratio of heat rate to CO2 rate. Metabolic heat rate was also measured as a continuous function of temperature by differential scanning calorimetry in the range of 10 to 40 °C. Tree growth was measured as rates of height and stem volume growth. The values of respiratory and growth variables of Eucalyptus species are significantly correlated with latitude and altitude of origin of their seed sources. The maximum metabolic heat rate, the temperature of the maximum heat rate, the temperature coefficients of metabolic rate, and the temperatures at which the slopes of Arrhenius plots change are all genetically determined parameters that vary both within and among species. Measurement of growth rate–respiration rate–temperature relationships guide understanding of why relative growth rates of Eucalyptus species and individual genotypes differ with climate, making it possible to identify genotypes best suited for rapid growth in different climates. The temperature dependence of respiration rates is an important factor determining relative growth rates of eucalypts in different climates. To achieve optimum biomass production the temperature dependence of individual plants must be matched to growth climate.


1967 ◽  
Vol 69 (3) ◽  
pp. 305-315 ◽  
Author(s):  
J. E. Jackson

Growth analysis of cotton crops sown in the Sudan Gezira at monthly intervals between August and May revealed a marked seasonal pattern of growth. Irrespective of plant age and fruiting state growth of non-senescent plants was slowest during the cool winter months. Relative growth rates of young plants were highest in August, September and early October due to the high specific leaf areas and fairly high net assimilation rates found then. They were lowest when minimum temperatures were lowest. Net assimilation rates were also lowest in the coolest months, probably as a result of restricted growth. High temperatures in the spring reduced fruiting. It is concluded that low minimum temperatures and high evaporation rates are both associated with slow growth, and play a large part in determining the characteristic decline of growth rates of cotton sown at the usual date in August.I wish to thank the Chief of the Research Division, Ministry of Agriculture, Sudan, for permission to publish this paper and to record my gratitude to the team of field and laboratory assistants, especially Salih Saad and Hassan Osman, who helped in the work.


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