The Hertz Corporation

About: The Hertz Corporation is a based out in . It is known for research contribution in the topics: Population & Soil water. The organization has 9562 authors who have published 11044 publications receiving 447929 citations. The organization is also known as: Hertz Rental Car & Hertz Rent-a-Car.

Ecological genetics of an induced plant defense against herbivores: additive genetic variance and costs of phenotypic plasticity.

Abstract: Adaptive phenotypic plasticity in chemical defense is thought to play a major role in plant-herbivore interactions. We investigated genetic variation for inducibility of defensive traits in wild radish plants and asked if the evolution of induction is constrained by costs of phenotypic plasticity. In a greenhouse experiment using paternal half-sibling families, we show additive genetic variation for plasticity in glucosinolate concentration. Genetic variation for glucosinolates was not detected in undamaged plants, but was significant following herbivory by a specialist herbivore, Pieris rapae. On average, damaged plants had 55% higher concentrations of glucosinolates compared to controls. In addition, we found significant narrow-sense heritabilities for leaf size, trichome number, flowering phe- nology, and lifetime fruit production. In a second experiment, we found evidence of genetic variation in induced plant resistance to P. rapae. Although overall there was little evidence for genetic correlations between the defensive and life-history traits we measured, we show that more plastic families had lower fitness than less plastic families in the absence of herbivory (i.e., evidence for genetic costs of plasticity). Thus, there is genetic variation for induction of defense in wild radish, and the evolution of inducibility may be constrained by costs of plasticity.

Persistent pesticides in the environment

Abstract: The persistence, sources, fate and possible control of pesticides are reviewed and discussed. The amounts of pesticides in soil, air, freshwater, seawater, soil and aquatic invertebrates, plants, fish, birds, other vertebrates, human food and human beings are summarized. The ways the amounts of these residues can be decreased are discussed.

Effects of potentially toxic metals in soil derived from past applications of sewage sludge on nitrogen fixation by trifolium repens L

Abstract: The growth and N2-fixation of Trifolium repens was measured in pots, using 15N techniques, on either metal-contaminated or uncontaminated soils which came from field plots which last received sewage sludge (contaminated) or farmyard manure (uncontaminated) more than 20 years ago. Plants grown on sludged soil had lower concentrations of N and smaller yields; the root nodules were small, white, numerous and ineffective in N2-fixation. By contrast, nodules on plants grown on farmyard manure-treated soil were pink (indicating the presence of leghaemoglobin), large and few in number, characteristic of effective nodules. The depressive effect on yield was overcome, at least in the short-term, by adding nitrogen fertilizer to the soil. Concentrations of metals in the leaf material were low and direct phytotoxic effects unlikely. The two soils were mixed in various proportions to test the effects of increasing concentrations of extractable metals in the soil on N2-fixation. A 50% reduction in fixation was observed in soil containing approximately the following concentrations (mg kg−1) of metals extracted by EDTA: 165Zn, 60 Cu, 7.3 Ni and 5.3 Cd. Corresponding “total” concentrations (mg kg−1) were 334 Zn, 99 Cu, 27 Ni and 10 Cd. These results are discussed in relation to the current guidelines designed to limit the accumulation of metals in agricultural soils receiving sewage sludge.