Tomatoes supports

Besri M (1982) Solar heating (solarization) of tomato supports for control of Didymella lycoper-sici Kleb. stem canker. Phytopathology 7 939... 

The carotenoid pathway may also be regulated by feedback inhibition from the end products. Inhibition of lycopene cyclisation in leaves of tomato causes increase in the expression of Pds and Psy-1 (Giuliano et al, 1993 Corona et al, 1996). This hypothesis is supported by other studies using carotenoid biosynthesis inhibitors where treated photosynthetic tissues accumulated higher concentrations of carotenoids than untreated tissues (reviewed by Bramley, 1993). The mechanism of this regulation is unknown. A contrary view, however, comes from studies on the phytoene-accumulating immutans mutant of Arabidopsis, where there is no feedback inhibition of phytoene desaturase gene expression (Wetzel and Rodermel, 1998). 

Diffusion-mediated release of root exudates is likely to be affected by root zone temperature due to temperature-dependent changes in the speed of diffusion processes and modifications of membrane permeability (259,260). This might explain the stimulation of root exudation in tomato and clover at high temperatures, reported by Rovira (261), and also the increase in exudation of. sugars and amino acids in maize, cucumber, and strawberry exposed to low-temperature treatments (5-10°C), which was mainly attributed to a disturbance in membrane permeability (259,262). A decrease of exudation rates at low temperatures may be predicted for exudation processes that depend on metabolic energy. This assumption is supported by the continuous decrease of phytosiderophore release in Fe-deficient barley by decreasing the temperature from 30 to 5°C (67). 

Other dietary factors implicated in prostate cancer include retinol, carotenoids, lycopene, and vitamin D consumption.5,6 Retinol, or vitamin A, intake, especially in men older than age 70, is correlated with an increased risk of prostate cancer, whereas intake of its precursor, [3-carotene, has a protective or neutral effect. Lycopene, obtained primarily from tomatoes, decreases the risk of prostate cancer in small cohort studies. The antioxidant vitamin E also may decrease the risk of prostate cancer. Men who developed prostate cancer in one cohort study had lower levels of l,25(OH)2-vitamin D than matched controls, although a prospective study did not support this.2 Clearly, dietary risk factors require further evaluation, but because fat and vitamins are modifiable risk factors, dietary intervention may be promising in prostate cancer prevention. 

In further work on this series, the same methods were used for the examination of the action pattern of highly purified pectinesterase produced by Fusarium oxysporum f. sp. vasinfectum.49 This pectinesterase was found to affect highly esterifled pectin by a mechanism similar to that of tomato pectinesterase, that is, more than half of the enzymic activity occurred at the reducing ends of the molecules, and the rest attacked a different locus or loci of the pectin chains. These conclusions were supported by a comparison of the effect of clostridial lyase on pectin partly de-esterified in an alkaline solution with its effect on pectin partly de-esterified by Fusarium oxysporum pectinesterase. The lyase did not act on the randomly... 

Supporting stems In addition to the support given by twine, canes, or frames, bottomless pots filled with potting mix around the base of tomato plants will encourage rooting from the stem and hence a more stable plant. 

To support cordon tomatoes, attach a length of twine to the greenhouse frame above each plant, and tie the other end loosely around the stem at the base of the plant. As the plant grows, twist the tip around the string. Alternatively, tie the stem to a tall cane. Pinch out sideshoots as they appear for the best crop, and pinch out the growing tip of the cordon after four or five clusters of fruit have formed (see also p.251). Taller eggplants and peppers may also need support with canes and twine. 

Right, top) Training cordon tomatoes To support the tall stems, tie them in as they grow to twine tied to the greenhouse roof or to tall oanes. 

Erect supports for peas, climbing beans, and cordon tomatoes before you sow or plant. For climbing beans, make tepees of canes, or double rows of canes tied together at the top, with one plant at the base of each cane. The beans may need to be guided to their supports and tied in, but will then start to spiral up the canes unaided. Peas have tendrils that will cling to twiggy sticks or wide-mesh pea netting. 

Tomatoes respond especially well to vertical culture, since many of the fruit may rot if they touch the ground. Tomatoes are usually supported by 5-or 6-foot stakes or a trellis. Use stakes at least 1 1/2 inches square and drive them a foot or more into the ground. Plants are praned to one or two stems and tied loosely to the support at 8- to-12-inch intervals. 

While the evidence presented herein cumulatively supports the Involvement of the phloem In translocating PIIF out of wounded tomato plants, the velocity of transport appeared to be much slower than expected for phloem transport. When carefully measured from point to point In petiole tissue the velocity of assimilate out of leaves. In general. Is In the order of 1-5 cm/mln (7, . Our techniques do not allow direct measurements... 

The existence of tomatinases in fungal-tomato pathogens supports the idea that tomatine may play a role in resistance to fungal attack because these enzymes seem to act specifically on tomatine. Such a role is also supported by the finding that at least in F. oxysporum f. sp. lycopersici, tomatinase is produced during infection both in roots and stems... 

Interestingly, the conversion of 3-dehydro-24-e/ i-teasterone to 24-epi-teasterone follows the opposite direction of the proposed biosynthesis pathway. Feeding experiments support this observation Exogenously applied 3-dehydro-24-e/ /-teasterone was converted to 24-epj-teasterone as the major metabolite (95%), and to only traces (5%) of 24-epi-typhasterol [23]. Thus, it is very likely that there is a different pathway in tomato cell cultures. In addition, preliminary studies with protein extracts of Arabidopsis cell cultures also reveal differences in enzyme distribution and specificity depending on the origin of the culture [Winter, unpublished]. 

The PGase extraction scheme outlined below (see Support Protocol) is based on the properties of the enzyme from tomato (Pressey, 1986). Enzymes from other sources will probably require different extraction conditions. A more detailed discussion of common approaches to enzyme extraction is included (see Background Information, discussion of samples for pectic enzyme assays). 

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