"Real" and Feed Pollen of Lagerstroemia indica: Ecophysiological Differences

Abstract: Lagerstroemia indica is heterantheric, its flowers bearing two kinds of stamens: six peripheral stamens with long, curved filaments and large anthers producing blue-green pollen, capable of emitting pollen tubes and fertilizing ovules; or a central tuft of 35 - 40 smaller anthers producing yellow feed pollen that does not germinate and is collected by insects, mainly bees. The two types of pollen differ in volume, number of pores, pore intine protrusion, wall structure, pollenkitt quality, hydration state, viability at anthesis, longevity and mono- and disaccharide composition. Although total sugar concentrations (glucose, fructose and sucrose) are the same in both types, relative concentrations are different, "real" pollen being sucrose-rich (S / [G + F] = 1.2) and feed pollen glucose-fructose-rich (S / [G + F] = 0.3). A lower degree of dehydration, pore intine protrusion and higher monosaccharide content could make feed pollen more digestible for pollinators. On the other hand, the cytological features of "real" pollen (high dehydration, higher sucrose content) points to longer viability and reproductive function.     

Evaluation of neem, Azadirachta indica, with and without water management, for the control of culicine mosquito larvae in rice-fields

Applications of neem, Azadirachta indica (Meliaceae), to rice-fields were evaluated with the dual objective of controlling the culicine mosquito vectors of Japanese encephalitis virus (JEV) and enhancing the grain yield. Since crude neem products deteriorate under improper storage conditions, a laboratory bioassay was developed to screen neem cake powder against mosquito larvae, Culex quinquefasciatus. Only samples of neem giving over 90% bioassay mortality were used in field trials. When good quality neem cake powder was applied at the dose of 500 kg/ha, either alone or coated over urea, there was a striking reduction in the abundance of late instar culicine larvae and pupae. Only fourteen pupae were obtained over a period of 13 weeks in neem cake powder treated plots, and four in those treated with neem coated urea, compared with 101 in control plots. Both treatments were significantly less than the control, but on par with one another. In another field trial, neem cake coated urea was tested at 500 and 250 kg neem/ha in combination with water management practices. No reduction in efficacy was noted at the lower dose. Larval abundance in plots under water management alone did not differ significantly from the controls, but was significantly reduced when water management was combined with neem products. Two stable formulations, 'Neemrich-I' (lipid rich) and 'Neemrich-II' (azadirachtin rich), also gave good suppression of immature culicines. All the treatments with neem also gave higher grain yield than the control.(ABSTRACT TRUNCATED AT 250 WORDS)     

A standard procedure for the micropropagation of the neem tree (Azadirachta indica A. Juss)

Micropropagated shoots were initiated from leaf explants of the neem tree, Azadirachta indica A. Juss. Regardless of their origin, shoots were successfully produced by culturing leaf explants on Murashige and Skoog medium containing benzylaminopurine (1 mg l^–1), kinetin (0.8 mg l^–1) and adenine sulphate (6 mg l^–1) in complete darkness. These shoots were further multiplied on Murashige and Skoog medium containing benzylaminopurine (0.1 mg l^–1), kinetin (0.08 g l^–l) and adenine sulphate (0.6 mg l^–1). Within 32 weeks, 80 shoots could be produced from a single leaf explant (10 mm×10 mm). Fifty-five percent of these shoots rooted on Murashige and Skoog medium containing indolebutyric acid (1 mg l^–1) and all of these grew on transfer to soil. Received: 5 May 1996 / Revision received: 23 August 1996 / Accepted: 5 October 1996     

Efficacy of a novel neem oil formulation (RP03™) to control the poultry red mite Dermanyssus gallinae

Dermanyssus gallinae (Mesostigmata: Dermanyssidae) is the most harmful ectoparasite of laying hens, represents an occupational hazard for poultry workers, and a growing threat to medical science per se . There is increasing demand for alternative products, including plant‐derived acaricides, with which to control the mite. The present study investigated the efficacy of neem oil against D. gallinae on a heavily infested commercial laying hen farm. A novel formulation of 20% neem oil, diluted from a 2400‐p.p.m. azadirachtin‐concentrated stock (RP03?), was administered by nebulization three times in 1 week. Using corrugated cardboard traps, mite density was monitored before, during and after treatment and results were statistically analysed. Mite populations in the treated block showed 94.65%, 99.64% and 99.80% reductions after the first, second and third product administrations, respectively. The rate of reduction of the mite population was significantly higher in the treated block (P < 0.001) compared with the control and buffer blocks. The results suggest the strong bioactivity of neem, and specifically of the patented neem‐based formulation RP03?, against D. gallinae . The treatment was most effective in the 10 days following the first application and its effects persisted for over 2 months. Further studies will aim to overcome observed side effects of treatment represented by an oily layer on equipment and eggs.     

Effects of <i>Piriformospora indica</i> on the Respiration of <i>Taxus chinensis</i> var. <i>mairei</i> under Water Stress

Seedlings of Taxus chinensis var. mairei were used as experimental materials to study the adaptation of Piriformospora indica to this plant under water stress. The materials were divided into two groups, namely, with or without inoculation with P. indica. Each group was subjected to four different levels of water stress. Vitality and physiological and biochemical indexes of the roots of T. chinensis var. mairei were regularly measured. Under water stress, T. chinensis var. mairei had significantly decreased root vitality; root vitality was higher in inoculated roots than in uninoculated roots. Under intense water stress, the inoculated roots had a higher soluble sugar content than the uninoculated roots. Under water stress, T. chinensis var. mairei experienced decreased activity of aerobic respiratory metabolic enzymes. The activity of anaerobic respiratory metabolic enzymes and alcohol dehydrogenase initially increased and then decreased, whereas that of lactate dehydrogenase increased. The inoculated roots had a higher activity of respiratory metabolic enzymes than the uninoculated roots. As water stress was further intensified, the roots had significantly decreased activity of aerobic respiratory metabolic enzymes and significantly increased activity of anaerobic respiratory metabolic enzymes. The activity of respiratory metabolic enzymes decreased faster in the uninoculated roots than in the inoculated roots. This study demonstrated that Piriformospora indica plays a positive role in enhancing the antihypoxic ability of T. chinensis var. mairei, thereby alleviating plant damage due to water stress.     

Effect of Different Amendments on Growing of Canna indica L. Inoculated with AMF on Mining Substrate

Canna indica L. (CiL) was used here in phytoremediation of mining soils. Our work evaluated the effect of AMF (i) on the growth and (ii) on the uptake of heavy metals (HM). The tests were conducted in the greenhouse on mining substrates collected from the Kettara mine (Morocco). The mine soil was amended by different proportions of agricultural soil and compost and then inoculated with two isolates of AMF (IN1) and (IN2) of different origins. After six months of culture, the results show that on mining soils (100%) only AMF (IN2) was able to colonize the roots of CiL with a frequency of 40 ± 7% and an intensity of 6.5 ± 1.5%. Also, the lowest values of shoot and root dry biomass are obtained on these mining soils with respectively 0.30 g and 0.27 g. In contrast, the accumulation of HM was higher and reached more than 50% of that contained in the mining soils, the highest values with 138 mg kg^?1 Cu²⁺, Zn²⁺ 270 mg kg^?1 and 1.38 mg kg^?1 Cd was recorded. These results indicate that the colonization of CiL roots by AMF (IN2) could significantly improve its potential to be used in phytoremediation of polluted soil.     

Removal of the pericarp and testa of seeds of japonica and indica rice (Oryza sativa) at various oxygen concentrations has opposite effects on germination

The germination of intact, dehusked, and peeled seeds (caryopses) of the japonica rice cultivar Sasanishiki, harvested 30, 40, 47 and 60 days after anthesis, and of the indica rice cultivar Assam IV, harvested 14 and 28 days after anthesis, was examined. Dehusking strongly inhibited germination of Sasanishiki seeds, with the exception that seeds harvested 30 days after anthesis gave minimal germination percentages even when left intact. Peeling (removal of the pericarp and testa) restored or enhanced germination, and 60–100% of seeds germinated after 10 days. By contrast, the rank order of germination of Assam IV seeds was intact, dehusked, and peeled seeds, with peeled seeds yielding germination percentages of 100%. In Sasanishiki, inhibition of germination of peeled seeds was observed at reduced oxygen concentrations (1–4% oxygen). This inhibition might explain the inhibitory effects of dehusking on germination of seeds from the japonica cultivar. It is possible that the testa and pericarp, which cover the embryos of dehusked seeds, acted as a barrier to the diffusion of oxygen to the embryo.