|
|
Honey bee publish details |
| More
Information |
|
|
| Name |
Y. Q. Ma, J. M. Chenga, S. Inanaga and J. F. Shui |
|
|
| Category |
Practice |
|
|
| Title |
WEED CONTROL |
|
|
| Details |
Induction and Inhibition of Striga hermonthica
Y. Q. Ma, J. M. Chenga, S. Inanaga and J. F. Shui
Excerpted with permission from Agron. J. Sept-Oct, 96(5)1349-1356, 2004. Induction and Inhibition of Striga hermonthica (Del.) Benth. Germination by Extracts of Traditional Chinese Medicinal Herbs (2004), copyright American Society of Agronomy.
Dr. Yong Qing Ma and his colleagues carried out a study to test whether traditional Chinese herbs could be used to treat Striga hermonthica infestation in Sub-Saharan Africa. The paper was published in the Agronomy journal in 2004. This article is a shortened and modified version of the paper.
Striga hermonthica (Del.) Benth. is a root parasitic weed that is known to significantly reduce the cereal production in the semiarid regions of Sub-Saharan Africa. Many countries in the region practise monocropping for cereals like sorghum, maize and millet. These crops are highly vulnerable to S. hermonthica infestation. In its lifespan, Striga hermonthica can produce 50,000 seeds which form a large seed reserve in the soil.
To deal with the accumulating seeds, one has to either stimulate faster germination or inhibit the germination altogether. The chemicals that stimulate Striga hermonthica germination include kinetin, zeatin, gibberellic acid, strigol, sorgolactone and alectrol. These chemicals are costly and are not suitable for weed control of relatively low-revenue crops like sorghum and millet. On the other hand, fungal toxins have been known to inhibit S. hermonthica germination. However, the authors claim that the control of S. hermonthica seed growth using Chinese medicinal herbs had not yet been documented till then. If, indeed, these herbs are effective against the weed, this could not only solve the existing problems but also provide a valuable alternative crop to the farmers of Sub-Saharan Africa.
Dr Ma and his fellow researchers, therefore, collected 383 traditional medicinal herbs from herbal medicine shops located in Shijiazhuang in the north and the Guangxi Province in the south of China. They air-dried the utilisable part of the herbs and powdered them as per the traditional Chinese herb powdering techniques.
For germination assays, aqueous and methanol extracts were tested using undiluted and 10 fold dilution for their ability to induce S. hermonthica germination. The positive control comprised seeds treated with GR24, a synthetic strigol analogue, to indicate the normal germination rate of S. hermonthica seeds.
Similarly, an inhibition assay was prepared with undiluted and 10-fold diluted aqueous herb extracts to test for inhibition efficacy of the medicinal herbs. The same could not be done with methanol extracts due to shortage of funds. Ma and his fellow researchers found that extracts from 26 plants dissolved in distilled water and 22 plants dissolved in methanol promoted germination.
Aqueous extracts from 27 herbs inhibited the germination of S. hermonthica. Among these, sixteen herbs were found to reduce the germination by more than 50 per cent when compared with the positive control. Curcuma long L. extracts completely inhibited germination while others like Pyrola calliantha H. Andres, Dichroa febrifuda Lour., Atractylo deschinensis Koidz., Atractylo desmacrocephala Koidz., Commi phoramyrrha Engl., Sinomenium acutum(Thumb.) Rehd., and Micromelum falcatum(Lour.) Tanaka strongly inhibited germination. Even 10-fold diluted extracts of A. chinensis, A. macrocephala, C. Myrrhia, C. aeruginosa, D. febrifuga, M. bealet, P. calliantha, and S. acutum exhibited strong inhibitory effects (<10% germination).
However, future studies could be done in S. hermonthica infested areas by introducing useful herbs into cropping systems. These herbs could stimulate early S. hermonthica germination while at the same time provide a high-value alternative crop used for treating human and livestock diseases. Studies on the influence of soil conditions on the activity and persistence of the active substance(s) in the extracts from these plants as well as activity of root exudates are also required to know how much and in what form the extracts can be used. |
|
|
| Volume No. |
Honey Bee 22(3) 19, 2012 |
|
 
|
|
