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A Bowman-Birk inhibitor with activity against gut proteases of Helicoverpa armigera was extracted in 0.1 M sodium phosphate buffer from defatted seed flour of Albizia lebbeck. It was purified to 29.62 folds with 51.43% recovery using ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-100 column and ion exchange chromatography on DEAE-Sephadex A50. The purified protein had a molecular weight of 12,303 daltons as determined by SDS-PAGE. It was found to be heat stable up to 60°C and had two pH optima of 7.5 and 9.0. The inhibitor exhibited non-competitive pattern of inhibition with a low Ki value of 0.2 μM. The inhibitor was found to be susceptible to varying concentrations of reducing agents like DTT and 2-mercaptoethanol, thereby indicating the role of disulphide bridges in maintaining its three dimensional structure and stability. The purified inhibitor caused mortality and suppressed larval growth of Pieris brassicae larvae. It was also found to be effective against gut trypsin extracted from Spodoptera littoralis. The sequence of the genes encoding for such inhibitors can be determined and the genes expressing protease inhibitors can be used in vegetable crops to confer resistance against insect pests and other plant pathogens.

A highly reproducible and efficient in vitro shoot regeneration system was developed in a potential medicinal plant, Albizia lebbeck using root explants. Root explants from 15 day-old-aseptic seedlings were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations (0.5, 2.5, 5.0, 7.5 and 10.0 μM) of 6-Benzyladenine (BA), Kinetin (Kn), 2-Isopentenyl adenine (2-iP) singly as well as in combination with α-Naphthalene acetic acid (NAA) (0.1, 0.5, 1.0, 1.5 and 2.0 μM). The highest rate of shoot multiplication (16.0 ± 1.87 for the average shoot number and 5.16 ± 0.38 cm for shoot length) was achieved on MS medium supplemented with 7.5 μM BA and 0.5 μM NAA. The effects of medium type, medium strength, pH and subculture on shoot induction and proliferation were also tested. An average of 21.6±2.87 shoots per explants could be obtained following this protocol. Rooting was achieved on microshoots using half strength MS medium with 2.0 μM Indole-3-butyric acid (IBA) after four weeks of culture. The in vitro raised healthy plantlets were successfully established in earthen pots containing garden soil and grown in greenhouse with >80% survival rate.

Three pod lengths ( 20 cm) and 13 pre-sowing treatments were considered with four dates of collection (9 February, 19 February, 1 March and 11 March) to investigate their effect on germination rate and growth of seedlings of Albizia lebbeck (L.) Benth. at Pundibari, West Bengal, India. The best time of pod collection was on 19 February as the germination rate of the seeds collected on this date was 92.5% without requiring any pre-sowing treatments. This clearly indicated that the seeds collected on 19 February were nondormant, viable and physiologically mature. Significantly better seedling growth was also obtained when the seeds were sown on 19 February which was extracted from pods of length 10–20 cm. Application of thiourea as a pre-treatment did not significantly enhanced seed germination rate, but its application in lower concentration (100 μL-L-1) resulted in better seedling growth and development.

A study was conducted on high-density young plantations of three native trees (Albizia lebbeck, Albizia. procera and Tectona grandis) and one native woody grass species (Dendrocalamus strictus) to examine their influence on total nutrient concentrations of coal mine spoil during early phase of plantation establishment. Soil samples were analyzed for total organic carbon (SOC), Kjeldahl nitrogen (TKN) and phosphorus (TP) at spoil depths of 0–10 and 10–20 cm under 4-and 5-year-old plantations of all species. A significant effect on concentrations of total SOC, TKN and TP were observed due to plantation age, species and soil depth. However, corresponding concentrations (SOC, TKN and TP) were substantially lower at spoil profile of 10–20 cm. In comparison, plantation of A. lebbeck showed greater SOC and nutrient concentrations followed by D. strictus, A. procera and T. grandis, respectively. Therefore, present study clearly indicates attributing qualities of plantation towards improving redeveloping soil of mine spoil varied with species.

An experiment was conducted to assess the effect of Phosphorous (P) fertilizer (i.e. TSP or triple super phosphate @ 80 kg/hm2) on seedling growth and nodulation capabilities of three potentially important agroforestry tree species (Acacia auriculiformis, Albizia lebbeck and Albizia procera) of Bangladesh. The study was conducted in nursery beds with six-month-old polybag seedlings of A. auriculiformis, A. lebbeck and A. procera. The effects of P fertilizer on seedling growth and nodulation were compared with that of the seedlings grown in control (i.e. unfertilized soil). The observations revealed that the seedling growth was enhanced significantly with the application of P fertilizer. The growth was found more pronounced in A. auriculiformis, whereas it was not apparent and shows depressed growth in case of A. lebbeck. The study also suggests that the nodulation in terms of nodule number and size was also increased significantly with the application of P fertilizer.

An experiment was conducted to observe the inhibitory effects of the leaf extracts derived from Albizia lebbeck (L.) Benth. on germination and growth behavior of some popular agricultural crops (receptor) of Bangladesh. Experiments were set on sterilized petridishes with a photoperiod of 24 h at room temperature of 27–30°C. The effects of the different concentrations of aqueous extracts were compared to distil water (control.). The aqueous extracts of leaf caused significant inhibitory effect on germination, root and shoot elongation and development of lateral roots of receptor plants. Bioassays indicated that the inhibitory effect was proportional to the concentrations of the extracts and higher concentration (50%–100%) had the stronger inhibitory effect whereas the lower concentration (10%–25%) showed stimulatory effect in some cases. The study also revealed that, inhibitory effect was much pronounced in root and lateral root development rather than germination and shoot growth.