PROGRAMACIÓN DE FÍSICA DE 2ºBACHILLERATO
BLOQUE 6. FÍSICA DEL SIGLO XX
5.2 DETERMINACIÓN DE LOS ESTÁNDARES MÍNIMOS DE APRENDIZAJE
new soft growth can be “pinched out” using just a thumb and forefinger. This reduces extension growth from that point and encourages the formation of sideshoots and enhances bushiness. It is often carried out on seedlings and young plants to prevent them becoming tall and spindly, but pinching out can be carried out on any plant with soft growth.
disbudding is the removal of surplus buds. This is normally performed on fruit trees to prevent a plant from forming too many flower buds and subsequently too much fruit. It is used to control the amount and quality of fruit. The process can also be used on plants grown purely for their flowers; it presupposes that a plant can only produce a certain total quantity of flowers, so if bigger flowers are desired, their number must be reduced. This applies not only to the size, but also to the quality, since the available nutrients and water are divided between fewer flowers.
Prunus domestica (plum). using a wound paint after pruning Prunus
species may help as an extra precaution against silver leaf disease.
Remove sideshoots from cordon tomatoes to encourage upright growth and crops of larger, better fruit
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P r u n I n G
deadheading
The process of removing flowers when they are fading, dying, or dead is known as deadheading. It is done to keep plants looking attractive (as dead flowerheads are often untidy in appearance) and, where plants have the potential to do so, it encourages them to make a further display of flowers.
once the flowers have been pollinated, seed and fruit development begins, and this often sends signals to the rest of the plant so that further flower develop- ment is retarded. regular deadheading prevents seed and fruit being produced and prevents energy being wasted on their production. This extra energy is redirected into producing stronger growth and sometimes further flowers.
Plants that are commonly deadheaded include bedding plants, bulbs, and many herbaceous perennials. While bulbs do not produce further displays, deadheading will prevent them from wasting energy on seed production, ensuring the energy is used instead for the following year’s flowers. remove the developing seed capsule but leave the green flower stalk in place until it dies, as this produces food through photosynthesis.
It is not often necessary to deadhead flowering shrubs, since many are pruned each year after flowering anyway (see p. 172), nor is it practical. some shrubs, however, particularly those with large flowers, will benefit from deadheading, and these include camellias, rhododendrons, lilacs (Syringa), roses, and tree peonies.
some gardeners talk of “liveheading” their plants. It is practiced on a number of late-summer herbaceous perennials to encourage later and bushier displays. The emerging flowerheads are cut back once in early to midsummer (no later) and allowed to regrow. Plants that respond to liveheading are asters, phloxes, and heleniums.
B O t A N y i N A C t i O N
Post-pruning feeding
After pruning, it is a good idea to feed the plants with a fertilizer. As plants store a lot of food reserves in their stems, cutting them off reduces the overall amount of stored reserves and it is important to encourage good regrowth after pruning.
Liquid feeds will give a quick boost, but are short-lived; granular feeds last longer; controlled- release fertilizers feed for several months. Most flowering trees, shrubs and climbers respond well to feeding with a high-potash granular feed.
As a plant’s feeder roots are mainly distributed at the edge of the leaf canopy, the feed should be spread in a circle in this area. Some gardeners erroneously apply the feed at the base of the stems where there are few feeder roots to make use of it.
After feeding, water the soil to activate the fertilizer and add a thick mulch of organic matter, such as well-rotted manure, garden compost, or composted bark, to keep the soil moist. See p. 152 for more about plant fertilizers.
Helenium sp, sneezewood
Faded flower and developing seed head
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M
arianne north was an english botanical artist and naturalist. she traveled widely to satisfy her passion for painting flora from all around the world.Initially, she had planned to be a singer and trained as a vocalist, but sadly her voice failed. as a result, she changed career aspirations, painting flowers and pursuing her ambition of painting the flora of other countries.
from the age of twenty-five she traveled extensively with her father, but after his death, which had a profound effect on her, Marianne decided to travel farther by herself. Her globetrotting was inspired by these earlier travels and the plant collections she saw at the botanic Gardens, Kew.
she began her travels at the age of forty-one, first going to Canada, the usa, Jamaica, and then on to
brazil. Then, in 1875, after a short spell in tenerife, she began a two-year journey around the world, painting the flora and landscapes of California, Japan, borneo, Java, Ceylon, and India and capturing them in oil paint.
fortunately for Marianne she was well connected, thanks to her father’s political career, and made use of contacts who supported her in her travels, including the President of the usa and the poet Henry Wadsworth Longfellow. In the uK, Marianne had many supporters including Charles darwin and sir Joseph Hooker, then director of Kew.
despite all these famous connections, Marianne preferred to travel unaccompanied and visited many areas unknown to most europeans. she was at her happiest when discovering plants in the wild, sur- rounded by their natural habitat, and painting them. some of the plants Marianne painted were new to science and some were named after her.
on her return to britain, she had several exhibitions of her botanical paintings in London. she then offered her complete collection of paintings to the royal botanic Gardens, Kew, and even proposed to build a gallery to house them. The Marianne north Gallery first opened in 1882 and is still open today. It is the only permanent solo exhibition by a female artist in britain. Visitors to Kew Gardens can enjoy this Victorian treasure house in all its glory and view the remarkable botanical art collection of this pioneering painter.
even then, her traveling days were not over. In 1880, at the suggestion of Charles darwin, she went to australia and new Zealand and painted there for a year. In 1883, following the opening of the Marianne north Gallery, she continued to travel and paint, visiting south africa, the seychelles, and Chile.
M a r i a n n e N o rt h
1 8 3 0 – 1 8 9 0
Marianne north was a 19-th century artist who traveled many parts of the world recording with her paintbrush the flora she found there.
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“ I h a d l o n g d r e a m e d o f g o i n g t o s o m e t r o p i c a l c o u n t r y
t o pa i n t i t s p e c u l i a r v e g e tat i o n o n t h e s p o t i n
n at u r a l a b u n d a n t lu x u r i a n c e . . .”
The remarkable scientific accuracy of her paintings gives her work a permanent botanical and historical value. Her paintings of Banksia attenuata, B. grandis, and B. robur are very highly regarded. a number of plant species were named in Marianne north’s honor, including Crinum northianum (a synonym of Crinum asiaticum), Kniphofia northiae, and Nepenthes northiana, as well as the genus Northia (family Sapotaceae), endemic to the seychelles.