Fruit pollination

More than 20% of insects are pollinators. Bees alone pollinate more than 50 agricultural crops [111]. When fully pollinated, fruit and berry plants grow 30-40% more, and melons and squash twice as much, or more. Bees increase harvest size 3-4 times in feed grass like alfalfa, red clover, and vetch [111]. However, the number of bees and other plant pollinators sharply and universally decreased in regions of the USSR where chemicals were used in agriculture in the middle of the 1980s. Because of this decrease, harvest size of some plants has noticeably decreased (for example, buckwheat and melons). 

Insects are considered to be another potential vector for faecal material to produce in production areas (Geldreich et al., 1964). Pollinating insects might inoculate flowers with pathogens opening the pathway for fruits to internalize pathogens and eliminating their accessibility to surface decontamination (De Roever, 1999). 

Observations Observation on each plant is recorded for fertilization for 1-2 days after the pollination. Formation of fruits and seeds lasts during 1-1.5 months. 

Anthocyanins are colored flavonoids that attract animals when a flower is ready for pollination or a fruit is ready to eat. They are glycosides (i.e., the molecule contains a sugar) that range in color from red, pink, and purple to blue depending on the number and placement of substitutes on the B ring (see Fig. 3.7), the presence of acid residues, and the pH of the cell vacuole where they are stored. Without the sugar these molecules are called anthocyanidins. The color of some pigments results from a complex of different anthocyanin and flavone molecules with metal ions. 

Obviously, pollinators are indispensable to most flowering plants. What is more easily overlooked is that they are critical to our own survival as well. Agriculture feeds the world, and about two-thirds of the world s crops require visits by animal pollinators to set fruit and seed. Various kinds of bees pollinate 60 percent of these crop plants, honey bees being the most important single species in this regard. In the United States alone, their contribution to crop pollination is worth billions of dollars every year. 

A few other kinds of flowers have adopted the orchids trick of trading odoriferous chemicals for pollination. The bees also harvest chemicals from decaying, fungus-infected logs, rotting fruit, and animal feces. Chemicals from other flowers are similar to the ones from orchids, but decaying logs furnish substances not available elsewhere. 

In general, the control of insect pests of cacao has been neglected. Also, little is known regarding the effect of insecticides on cacao. Cardona (9) in Colombia has studied the influence of some insecticides on the pollination and fruit setting. He used various preparations of BHC Agrocide, chlordan, DDT, dieldrin, dieldrex, methoxychlor [l,l,l-trichloro-2,2-bis(p-methoxyphenyl) ethane], and toxaphene. 

Chemical weed control in cacao plantations with volatile weed killers is generally considered detrimental to pollinating insects and to the flower and fruit set. Recently Naundorf (28) and Oliver (33) in Colombia conducted tests with compounds derived from 2,4-D and with an ammonium salt of dinitro-o-cresol to determine the effect of these materials on the flowers. They found that dinitro-o-cresol can be used at the dosages commercially recommended, and that only the volatile 2-4-D derivatives at concentrations of 500 to 750 grams per plaza (6400 square meters) can be used. 

Bees, especially orchard mason bees, which are useful fruit tree pollinators, will colonize holes drilled in blocks of wood or paper drinking-straws stacked in a waterproof box, or you can buy special bee boxes. Mason bees emerge early, so the boxes need to be erected in early spring before the apple buds burst. 

In most cases, cucurbit plants bear flowers of two types, either male or female, and the latter must be pollinated by the former to set fruit. Female flowers have a tiny fruit behind the flower that swells once pollination has taken place. 

Flowers must be pollinated for fruit to form (see alsop.290). Some apples are "self-fertile"— pollination is achieved by bees flying from flower to flower on the same tree. Others cannot set a crop on their own and need to be planted within bee-flying distance of another cultivar that is both compatible and in flower at the same time. Your neighbors yard is usually close enough. A crab apple can also make an effective pollinator. 

To produce fruit, pears need to be pollinated by another compatible cultivar—that is, you need to grow two different pears—and their compatibility groupings are quite complex, so seek advice when you buy. A specialty fruit nursery or mail order company can advise you on appropriate combinations of cultivars. Pears are slower to start cropping than apples. It is well worth buying a tree grown for three years In the nursery to shorten the time before you harvest your first crop. 

For general advice, see Apples (p.294). Most European plums will set some fruit without cross-pollination, but nearly all will yield better when cross-pollinated by another European cultivar. Japanese plums must be cross-pollinated by either a Japanese or American type. American plums also need cross-pollination for best yields. Rootstock choice can further influence your plum trees success. Ask a specialty fruit nursery for help in selecting a suitable combination of trees on appropriate rootstocks. 

Hand-pollinating peaches A rabbit s foot is a traditional tool for pollinating peaches, but a soft paintbrush or cosmetics brush is just as effective. Lightly dab each open flower in turn, and you should transfer enough pollen from blossom to blossom to ensure that fruits form. 

This North American native plant makes a fine garden shrub with lovely fall coloring. A single plant will crop reasonably well two or more bushes to cross-pollinate each other will fruit much better. Fruiting will start in the second summer after planting, reaching full cropping after five or six years. 

Schemske DW, Bradshaw HD (1999) Pollinator preference and the evolution of floral traits in monkeyflowers (Mimulus). Proc Natl Acad Sci USA 96 11910-11915 Wang HC, Huang XM, Hu GB, Yang Z, Huang HB (2005) A comparative study of chlorophyll loss and its related mechanism during fruit maturation in the pericarp of fast- and slow-degreening litchi pericarp. Sci Hortic 106 247-257...

Essential oils are especially important in mutualistic relationships between plants and insects such as pollination and seed and fruit dissemination (37,45,77-79). In these instances essential oil components serve as attractive substances for the plant. These compounds vary widely in composition but contain most of the chemical types described above. In some cases even volatile amines and skatole are involved, as in the pollination of Sauronatum guttatum (Araceae) (80). 

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