Pears, formation

Diphenylamine inhibits the development of scald disease during prolonged cold storage of apples and pears (42—45). It prolongs the fresh appearance of cut snapdragons (46), controls weather fleck in tobacco, inhibits algae formation, and shows growth inhibitory activity in potatoes (47). 

Amyl Acetate.—This is, with the exception of amyl formate, which is not of practical importance, the simplest possible ester of amyl alcohol, and has the formula CHj. COO. CsHjj. It is a fruity oil, with a strong odour resembling that of the pear, and is known as art ficial oil of pear. It is prepared on a very large scale by, for example, treating 100 parts of dry sodium acetate, 100 parts of amyl alcohol, and 130 parts of sulphuric acid for twelve hours at ordinary temperature, and then distilling off the ester. It has a specific gravity 0-876, and boils at 138°. The alcohol in this ester is not normal amyl alcohol, but isoamyl alcohol. 

The electrical activity of a defect is characterized in part by its electrical level position, which can be determined by capacitance transient methods. When the capacitance transient spectra are monitored before and after exposure to atomic hydrogen, it is found in many systems that these levels disappear. This phenomenon has been associated with the formation of electrically inactive hydrogen-impurity complexes as summarized by Pear-ton et al. (1987) and in Chapter 5 of this volume. 

Our experience has shown that the hydrolysis of aluminium phosphide with cold water is the most suitable method for the laboratory preparation of phosphine. Here it is important that the aluminium phosphide be as pure as possible in order to avoid the formation of spontaneously inflammable phosphine. The presence of small quantities of diphosphine and also higher phosphines are responsible for this spontaneous inflammability 96.276-278) jj. gp, pears, however, that these are only formed when P—P bonds are already present in the phosphide. Accordingly the hydrolysis of aluminium phosphide, prepared from the elements with phosphorus in slight excess, always leads to spontaneously inflammable phosphine. The formation of diphosphine and higher phosphines from aluminium or alkaline earth metal phosphides, which contain excess phosphorus, can be easily understood when the lattices of these compounds are considered. 

Pears (1984, pp. 94ff) points to the difference between irrational intervention and failure to intervene rationally, and argues that irrational belief formation is to be explained in terms of the latter. 1 believe this captures many central cases, but I am still not sure it covers all important instances. 

The production of ethylene in fruit tissue and in small amounts in leaves may justify its consideration as a hormone, functioning in the gaseous state, Cherimoyas and some varieties of pear produce 1000 times the effective physiological concentration. Ethylene formation is closely linked to oxidation and may be centered in the mitochondria. Its effects are to promote cell-wall softening, starch hydrolysis, and organic add disappearance in fruits—the syndrome known as ripening. Ethylene also decreases the geotiopic responses of stems and petioles. 

Abscisic acid is a negative regulator in that it primarily antagonizes the action of cytokinins, auxins, and in particular, gibberellins. Abscisic acid decreased the activity of polymerase in radishes (52), peas (53), maize coleoptiles (54), and pear embryos (55). More detailed studies are needed before the question of ABA-induced "modification" of RNA polymerase (54) or "alterations" in the number of sites for template activity (56) can be answered. In barley aleurone cells, ABA-induced suppression of GA-induced <-amylase formation was presumed to involve the continuous synthesis of a short-lived RNA (57). 

Peroxidase has been implicated in the formation of the grit cells or stone cells of pears (Ranadive and Haard 1972). Bound peroxidase but not total peroxidase activity was higher in the fruit that contained excessive stone cells. The stone cells or sclereids are lignocellulosic in nature. The presence... 

Ranadive, A.S., and N.F. Haard. 1972. Peroxidase localization and lignin formation in developing pear fruit. J. Food Sci. 37 381-383. 

Take a dry 10 mL pear-shaped flask filled with argon and stoppered with a septum. To this add 0.5 M solution of bis(tri-/7-butylammonium pyrophosphate in DMF (1.2 mL, 0.6 mmol) prepared in Protocol 9, 2 mL of dry DMF and finally dry tri-/7-butylamine (290 p.L, 1.2 mmol). Vortex/mix this mixture for about 30 s and then add to the reaction immediately in one portion. Triphosphate formation may be monitored by ion exchange FIPLC (Protocol 6) or silica TLC (Protocol 7) but should be complete within 10 min. A typical silica TLC plate is shown in Figure 9.6. (Note In our experience, 3 eq. of the pyrophosphate/tributylamine is generally adequate in this step, although in some circumstances we have used 4 eq., notably for smaller-scale reactions. In this latter case, the triphosphate will probably require HPLC purification following MPLC in order to remove all the excess pyrophosphate—see Protocols 19 and 20). 

In many cases cultivated soils have compacted areas which can severely impair tree growth. Compaction in soil may be due to factors associated with soil formation or geology, or it may have been caused by mechanical pressure from machinery or by deposits by transport and ground-levelling vehicles. If the soil is compacted it is absolutely essential to loosen the subsoil (e.g. by trenching or deep cultivation) before a new orchard is set up. Dwarfing rootstocks for apples and pears (M9, M27, quince C), elder and small fruit trees are particularly sensitive to soil compaction. 

Methyl (E)-2-octenoate was found for the first time in pineapple. It had been previously reported in pears (22) and soursop (2. Its formation from methyl (E)-3-octenoate (a pineapple constituent) by 2,3-(E,E)-enoyl-CoA-isomerase was postulated by Berger and Kollmannsberger ( )... 

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