A promising method of micropropagation of Stevia rebaudiana Bertoni has been developed with an aim to increase the biomass, survivability of the plantlets and stevioside production, using chlorocholine chloride (CCC). Microshoots transferred to the MS medium containing different combinations CCC and IBA were found to be most effective in terms of growth pattern, hardening ability of the plantlets and stevioside content, compared to MS medium containing either IBA or CCC. Among other combinations tested, MS medium supplemented with 3 mg/l CCC and 3 mg/l IBA was found most effective in inducing significant changes like reduced shoot length, increased number of roots, higher leaf size, increased biomass and chlorophyll retaining capacity, higher survival percentage and most importantly the elevated stevioside content. Collectively, the major observations of this research indicate that application of CCC in micropropagation of S. rebaudiana Bertoni is a promising approach and has commercial prospects.

In pot experiments, foliar application of dikegulac sodium (2,3:4-6-di-O-isopropylidene-α-L-xylo-2-hexalofuranosate) at 500 and 750 μg/mL inhibited plant growth and decreased growth and dry matter production of the treated leaves of sunflower (Helianthus annuus L. cv. Modern). A concentration of 100 μg/mL, however, increased leaf area and anabolic activities of treated leaves. Increased cambial activity was noted at all concentrations of dikegulac, which resulted in formation of secondary tissues. At 500 and 750 μg/mL RNase and protease activities increased appreciably, while catalase activity was drastically suppressed. The inhibitory effect of dikegulac was also found in newly expanding leaves which developed after treatment. Beneficial effects of dikegulac at low concentration were also reflected in field experiments where increased yield was noted, while high concentrations were distinctly inhibitory. The importance of dikegulac as an agronomically promising chemical for sunflower is discussed.

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An attempt was made to evaluate the allelopathic potential of an exotic tree species, Melaleuca leucadendron L. using mung bean (Vigna radiata L.) seeds as responsive bioassay material. This was recorded in terms of the plant extract and plant leachate-induced changes of seed germination behaviour, the levels of DNA and RNA as well as amylase activity in the seed kernels. The results of the present investigation clearly revealed that pretreatment of mung bean seeds with various concentrations [1:1 and 1:2 (w/v)] of M. leucadendron bark extract, leaf extract and leaf leachates for 24 h duration, significantly reduced percentage seed germination and increased the T 50 hours. Levels of DNA and RNA were also significantly reduced with concomitant increase of amylase activity in mung bean seed samples pretreated with the bark extract, leaf extract and leaf leachates of M. leucadendron. Tender bark extract and leaf extract showed more inhibitory action on mung bean seed than leaf leachates. Putative allelochemical-induced inhibitory effect, that is, reduction of seed germinability along with stimulation of amylase activity in seeds, being the important allelopathic indices, it can be concluded that M. leucadendron can potentially render allelopathic action on the experimental bioassay material.