Leafy crops

Leafy crops Tobacco High yield, established transformation and expression technology, rapid scale-up, non-food/feed Low protein stability in harvested material, presence of alkaloids... 

The two major leafy crops used for the production of recombinant proteins are tobacco and alfalfa, both of which have high leaf biomass yields in part because they can be cropped several times every year. The main limitation of such crops is that the harvested leaves tend to have a restricted shelf life. The recombinant proteins exist in an aqueous environment and are therefore relatively unstable, which can reduce product yields [16]. For proteins that must be extracted and purified, the leaves need to be dried or frozen for transport, or processed immediately after harvest at the production site. This adds considerably to the processing costs. 

Indeed, some forms of brassica can be picked at almost any time of year. Leafy crops include kale and cabbages for winter, spring, and summer use. The immature flowerheads of broccoli, cauliflowers, and sprouting broccoli are eaten Brussels sprouts develop their small, cabbagelike edible heads along a tall stem. 

All prefer well-drained soil. Leafy crops can be fitted into a rotation or put among ornamentals cardoons and globe artichokes, which need space, look good in an ornamental border. The roots can join other root crops in a crop rotation, while Jerusalem artichokes make a good windbreak. Lettuce and endive do well in containers. 

Some vegetables—peas and sweet corn in particular, but also young and leafy crops—taste best when eaten as soon as possible after picking. However, most keep well for a few days in a cool garage or in the refrigerator. Potatoes, onions, carrots, and other root crops can be stored to feed you over the winter months. 

Larval pests that tunnel around feeding within leaves, creating characteristic maze patterns. They can be sguashed in their "mines" between finger and thumb, or leaves can be picked off. Damage tends to be more unsightly than harmful, except on leafy crops. 

Cadmium is present at low concentrations in most foods, with those that are consumed in larger quantities making the largest contribution to the population dietary exposure. Although the concentrations of cadmium in food in the UK are generally low, some foods of minor dietary importance such as shellfish or kidney often contain levels in excess of 0.5 mg/kg. Plant-based foods rarely contain more than 0.2 mg/kg on a fresh weight basis, although some root crops such as carrots and parsnip, and some leafy crops, such as spinach and lettuce, tend to contain more cadmium than other plant foods. This is also true of cereals, which indicates that plants tend to take up cadmium from the soil, unlike lead. 

Potassium contributes to the formation of sugars, carbohydrates, proteins and to cell division adjusts water balance enhances the flavor, color, and oil content of fruits and is very important for leafy crops. Potassium deficiency produces a spotted, curled, or burned appearance to leaves and lowers crop yields. Potassium fertilizers are applied in the following forms potassium chloride, potassium sulfate, potassium nitrate, and wood ash. 

The most common use of temperature for disease control is cold storage. In general, storing harvested crops at low temperatures slows the growth of possible pathogens. The optimum storage temperature, however, varies from crop to crop. Apples and many other harvested fruit, root, and leafy crops store best at temperatures as close to freezing as possible. The flavor of bananas and avocados, however, are ruined at such low temperatures. Similarly, winter squash, pumpkins, and sweet potatoes keep best at 50°-60°E... 

Apply compost or manure to those crops that need it most. Some crops prefer to feast on the leftovers of nutrients applied the previous year. This list includes members of the cabbage family, solanaceous plants such as tomatoes and potatoes, most root crops, and leafy crops like spinach and lettuce. Other crops, including squash family members, corn, and other grains, and legumes such as peas and beans prefer a fresh application of compost or manure each year. 

Residues from a leafy crop immediately after treatment were compared with acute and chronic studies where exposure is maintained for time frames that arc unreasonable fora compound like PBO, which dissipates rapidly in the environment. Furthermore, birds would not feed solely on the crop and field treated-Thus there is a presumption of no risk to avian wildlife species from use of PBO. 

The residue levels of PBO and HMDS for the assayed commodities are presented in Table 10.3. The results show that the highest residues of both PBO and HMDS were found on leafy crops (e.g. lettuce, mustard greens, etc.) which are directly exposed to the spray. Lower residues are found on fruits and less exposed stems (e.g. broccoli) and minimal residues are found in commodities which are not directly exposed (e.g. potato tubers). Little or no translocation of PBO or closely related metabolites occurred. Low residue levels of HMDS-producing metabolites were found away from tbe application site. The results confirm the findings of the radio label led metabolism studies. 

Plant fruiting crops (including tomatoes, beans, squash, etc., plants where neither leaves nor roots are eaten) rather than leafy crops (lettuce, spinach, etc.) or root crops (beets, potatoes, etc. ), which absorb more lead from the soil. 

If you do grow leafy crops, remove the outer leaves. These can contain as much as five times more lead than inner leaves. 

Avoiding growing leafy crops and root crops these absorb more lead than fruiting crops. 

Removing outer leaves from any leafy crop and peeling root crops before eating. 

D-Pructose, fruit sugar or laevulose, occurs free in green leaves, fruits and honey. It also occurs in the disaccharide sucrose and in fructans. Green leafy crops usually contain appreciable amounts of this sugar, both free and in polymerised form. The free sugar is a white crystalline solid and has a sweeter taste than sucrose. The exceptionally sweet taste of honey is due to this sugar. 

All farm crops except legumes (e.g. beans, peas, clover) especially important for leafy crops (e.g. grass, cereals, kale and cabbages)... 

Grass and other leafy crops respond throughout the season and about 25 mm of water can be applied every time the deficit reaches 30 rrun. Although intensive dairying is the most profitable way to utilise the extra production, it is unusual to irrigate the grass crop in the UK. 

This is a quick growing palatable leafy crop which is ready for grazing abont 12 weeks after sowing. It generally lacks winter hardiness and should therefore be used before the end of the year. 

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