The Control of Germination

Germination, as we have defined it, culminates in radicle emergence which in most cases comprises only cell enlargement and not necessarily cell division. Perhaps, then, when searching for specific germination events we should look 

No satisfactory answer can therefore be given to the key questions—what biochemical events are specific to germination and how are they controlled These are the central questions and at present most of our knowledge is marshalled around them. 

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Propyzamide is effective mainly for the control of germinating weeds. It is absorbed through the roots, in Agropyron repens also through the rhizomes when applied in their vicinity. The absorbed herbicide inhibits the root and stem growth of sensitive plants. After treatment, normal cell division stops within a short time. Thus, primary action is manifested by the inhibition of mitosis (Carlson et al.,... 

Finch-Savage, W.E. Leubner-Metzger, G. (2006). Seed dormancy and the control of germination. New Phytologist, Vol.171, No.3, pp. 501-523, ISSN 0028-646X Finkelstein, R.R. (1994). Mutations at two new Arabidopsis ABA response loci are similar to the abi3 mutations. Plant Journal, Vol.5, No.6, pp. 765-771, ISSN 0960-7412... 

The rate of germination of white clover seed was stimulated by 100 pM ferullc acid through the Initial 24 hr of the test (Table II). Germination of clover was delayed by 500 pM ferullc acid, but after 36 hr no differences were observed at 100 to 500 UM concentrations. High concentrations (1000-2000 pM) were consistently inhibitory. Radish seed germination was not affected by ferullc acid levels tested except at 24 hr when those In 500 PM were less than controls. 

The synthetic studies which have been described have resulted in significant improvements in the preparation of racemic strigol and have also provided access to several analogs which will subsequently be tested for seed germination activity in order to elucidate key structure-activity relationships. These results and further investigations will hopefully lead to effective synthetic compounds for the control of witchweed and related parasitic plants. 

Figure 2 reports the time dependent germination pattern of radish seeds in the presence and absence of rue extract. Although the germination curves have the same general shape, important differences between control and treated seeds are evident. In fact, the rue extract induces a delay in the onset and a decrease in the rate of germination. 

B.) The yield of recombinant HSA, as determined using an enzyme-linked immunosorbent assay (ELISA). The sprouts were germinated in an airlift bioreactor tank for 175 hours in the presence or absence of 20 mM KN03. Recombinant HSA was expressed under the control of the Rbc56 promoter isolated in our laboratory. 

Numerous other chemicals have been tested on nut grass. TCA delays the germination of tubers but does not materially reduce the stand. A combination of TCA and 2,4-D was superior to either chemical in Brazil (40). Methyl bromide has proved excellent for the control of nut grass in the United States (23) and on a small scale in Puerto Rico. Unfortunately, it is expensive and difficult to apply. CMU kills nut grass, especially if applications are alternated with plowing, but leaves the soil unusable for crops for an extended period and is too expensive for large scale application (28). 

Galau, G.A., Jakobsen, K.S. Hughes, D.W. (1991). The controls of late dicot enbryogenesis and early germination. Physiologia Plantarum 81, 280-8. 

The ALS inhibitors are at the highest risk for the selection of resistance in weeds because they have a single target site, are effective against a wide spectrum of weeds, are now used extensively on many crops, and are relatively persistent - often providing season-long control of germinating weed seeds (Brown et al., 1995). Also, the various sites of mutations for resistance are not near the active site of the enzyme. As a result, there is no fitness loss due to a lower affinity for the normal substrates (Christoffoleti et al., 1997). 

Quinoxyfen is a fungicide that is used for the control of powdery mildew diseases by interfering with germination, and, in some cases, such as barley powdery mildew, appressorium formation [170],... 

Limited data are available on immunological effects in animals after dermal exposure to PCBs. Dermal applicahon of an estimated 44 mg/kg/day Aroclor 1260, 5 days/week for 4 weeks resulted in moderate atrophy of the thymus in rabbits (Vos and Notenboom-Ram 1972). No treatment-related histological effects were observed in the spleen and lymph nodes. Application of an estimated 42 mg/kg/day of the same Aroclor for 38 days to rabbits produced histological atrophy of the thymus cortex and a reduction in the number of germinal centers in the spleen and lymph nodes (Vos and Beems 1971). No treatment-related effects were observed in control rabbits in either study. These studies tested small numbers of animals and used Aroclor 1260 that had undetectable levels (<1 ppm) of CDFs. 

Provide long-term soil residual and season-long control of germinating weeds, or applied many times throughout the year. 

Diphenamide is used for the selective control of germinating annual grass weeds and broad-leaved weeds at a rate of 4-6 kg active ingredient/ha in peanuts, peppers, tomatoes, strawberries and potatoes. The cause of selectivity is rapid metabolic degradation in tolerant plants. 

It is effective mainly for the control of monocotyledonous germinating annual weeds as a preemergence herbicide at rates of 0.8-2 kg/ha. Its effect is unsatisfactory in dry weather. Its action lasts for over one growing season. 

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