Interactive Effect of Elevated CO2 and Moisture Stress on Anatomical Configuration in Brassica Species

Free-Air CO2 Enrichment (FACE) was developed as a means to study the crops response to elevated level of CO2 under the fully open-air field conditions. In this study, results of FACE experiments are summarized by disusing the root and shoot anatomy. Result indicated that elevated Co2 significantly altered the root and shoot xylem and phloem characters such as both proto and meta xylem and phloem; vessels, character of root and shoots which are vital for the transpiration regulation, along with leaves photosynthesis as a whole. The coexistence of two ontogenetically different phloem sieve element in Brassica plant under elevated CO2 might have possibility of two different transport functions at the same time. One may be involved in supplying for the structural development (leaf size, stem girth and root volume) and other may cater the need of increased new sinks. Though these parameters were found to decrease under moisture stress condition but these impacts of stress were reduced at higher level of atmospheric CO2.

Deciphering Brassica plant defence responses to cabbage white butterfly egg-associated molecular patterns

Brassica plants activate a strong hypersensitive response (HR)-like necrosis underneath eggs of cabbage white butterflies, but their molecular response to eggs is poorly understood. Here, we developed a method to generate egg wash to identify potential insect egg-associated molecular patterns (EAMPs) inducing HR-like necrosis. We found that egg wash, containing compounds from Pieris eggs, induced a similar response as eggs. We show that wash of hatched eggs, of egg glue, and of accessory reproductive glands (ARG) that produce this glue, also induced HR-like necrosis, whereas removal of the glue from eggs resulted in a reduced response. Eggs of Pieris butterflies induced callose deposition, production of reactive oxygen species and cell death in B. nigra and B. rapa leaf tissue, also in plants that did not express HR-like necrosis. Finally, only washes from Pieris eggs induced defence genes and ethylene production, whereas egg wash of a generalist moth did not. Our results indicate that EAMPs are in the egg glue and that the response in B. nigra is specific to Pieris species. Our study expands knowledge on the Brassica-Pieris-egg interaction, and paves the way for identification of EAMPs in Pieris egg glue and corresponding receptor in Brassica spp.

Effects of Parasitoid Age, Host Egg Age, and Host Egg Freezing on Reproductive Success of Ooencyrtus mirus (Hymenoptera: Encyrtidae) on Bagrada hilaris (Hemiptera: Pentatomidae) Eggs

Bagrada hilaris (Burmeister) is a serious pest on brassica crops in many regions throughout the world. As part of our efforts to enhance biological control, we have been studying an egg parasitoid that was collected from B. hilaris eggs found on brassica plant debris in Pakistan. This species has recently been described as Ooencyrtus mirus Triapitsyn & Power. A major component of rearing biological control agents is understanding the relationship among host egg age, parasitoid age, and reproductive success. To this end, we used a factorial design to evaluate all combinations of host egg ages 0–5 d and parasitoid ages 0–11 d. The results showed that the best combinations are 0- to 1-d-old host eggs with 3- to 10-d-old parasitoids. A further study using frozen host eggs showed that O. mirus can reproduce as successfully on frozen B. hilaris eggs as on fresh ones.

Evaluation of the Physiological Host Range for the Parasitoid Ooencyrtus mirus, a Potential Biocontrol Agent of Bagrada hilaris

The thelytokous egg parasitoid Ooencyrtus mirus Triapitsyn and Power (Hymenoptera: Encyrtidae) was recovered from brassica plant debris in Pakistan in an effort to find a biological control agent of the invasive bug Bagrada hilaris (Burmeister) (Heteroptera: Pentatomidae) in North America. As the first step in determining the overall host range of this parasitoid, adult females were exposed to the eggs of eight alternate pentatomid host species, two non-pentatomid heteropterans, and two lepidopterans, in choice and no-choice tests. Although O. mirus was more successful on B. hilaris than the other species in terms of the number of the eggs laid, the number of emerged progeny, and the developmental time of the progeny, it was able to reproduce on all of the alternate hosts except for one of the lepidopterans, whose eggs appeared too small for this parasitoid. The results show O. mirus to be a generalist parasitoid species with a preference for B. hilaris. The results also indicate that there is a linear relationship between the mean body length of O. mirus females and the mean host egg weight with an adjusted R 2 of 0.90. The implications of this study on the release of O. mirus for the control of B. hilaris are discussed.

KEEFEKTIFAN LIMBAH TANAMAN BRASSICACEAE UNTUK PENGENDALI NEMATODA PURU AKAR (MELOIDOGYNE SPP.) PADA MIKROPLOT DI LAPANGAN

Effectivenes of Brassicaceae plant wastes to control the root knot nematodes (Meloidogyne spp.) at a field microplot scale. Meloidogyne spp. is a soil borne pathogen that infects plant roots and causes root galls. Root knot nematodes can reduce crop production by 15 to 95%, so that the control measures are needed. One of the control methods is using plants as biofumigant. Plants of the family Brassicaceae were reported contain glucosinolate (GSL). During decomposition, GSL is hydrolized to isothiocyanates (ITS) which is a highly toxic compound to soil organisms, including nematodes. The research objective was to determine the effectiveness of five Brassicaceous plant wastes, namely cabbage (B. oleracea var capitata), radish (Raphanus sativus), broccoli (B. oleracea var italica), chinese cabbage (B. chinensis) and pakcoy (B. rapa var parachinensis) to suppress root knot nematodes (RKN). The experiment was conducted on microplot scale in the field. The experimental design used was a 4x5 factorial CRD. The first factors are waste of Brassica and the second factors are the amount of Brassica wastes per microplot. The experiments were made in 6 replications. Application of 5 Brassica plant wastes at all doses tested effectively reduced the number of root knot by 45.65% to 94.43% and increased the average number of tomato fruits. Tomato plants grew better at microplots when treated with chinese cabbage and pakcoy wastes.

Cadmium stabilization by plant growth promotory fluorescent Pseudomonas in combination with Indian mustard var. Kranti

Two cadmium resistant fluorescent Pseudomonas strains, originally isolated from oil contaminated sites were tested for their plant growth promotory properties and cadmium stabilization in combination with Indian mustard var kranti (Brassica juncea) in a pot experiment. Both the strains showed 99% homology to Pseudomonas aruginosa and were positive for all five plants growth properties like siderophore, IAA, hydrogen cyanide, Ammonia production and phosphate solubilization. Growth and health of plants in all the measured parameters under controlled conditions in insitu experiment was inhibited in the presence of cadmium, as indicated by a decrease in measured values of plant health. However, in the presence of fluorescent Pseudomonas strains, all the parameters of plant health showed improvement over the control with decrease in cadmium uptake by the plant as revealed by atomic absorption spectrophotometry. The presence of test strains stabilizes cadmium in the rhizosphere with less uptake of cadmium by the plants and siderophore property helps plant combat abiotic stress posed by cadmium. This technology [Phytobioremediation: Synergistic use of plants and microbes in bioremediation] enables the remediation of cadmium contaminated wastelands for raising Brassica plant for feed and fodder without any harm in combination with the test strains used in the present study.