Page 150 - Complete IELTS Bands 5 - 6.5

C02 Track 23 Another adaptation not directly connected w1th water but w1th
surv1val1s found on someth1ng like the Pnckly Pear Cactus
In today's lecture. I'm gomg to contmue our work on plants
There are hundreds of these 1n the Mex1can desert I'm sure
and talk about plants that live 1n the desert Now. JUSt a bit of
you've seen them on films and adverts Um. y~s. so because
background 1nformat1on first As you know. about a th1rd of the
desert plants store water 1n the1r spongy t1ssue. ammals Will
world IS covered 1n desert. and the sort of area they're found
eat them. So the plant has sharp thorns spec1ally des1gned to
1n 1s Important Deserts are usually created because the area
prevent the predator from be1ng able to - well. get near 1t at all
of land where they he 1s located 1n somethmg that's called a
'ra1n shadow' Now. th1s IS a reg1on that's beneath a mountain Our next plant 1s called the Desert Spoon Th1s plant has long
range, and what happens 1s that the w1nd blows over the leaves that fan out. and they're very succulent because they
mounta1ns towards the area, but as 1t does so. the aw loses 1ts can also store water 1ns1de. However. they're also usually very
mo1sture and becomes very dry. tough. and this helps keep the water 111S1de and also makes
them less tasty.
Because of th1s 'downwind' location, ra1nfall often totals JUSt
a few 1nches a year or. 1n some reg1ons. there's absolutely F1nally, we come to the Aloe Plant Th1s IS one that many
none And you can 1mag1ne the effect of th1s It means that people keep 1n the1r homes. It's an attractive plant wh1ch has
whatever ra1n does fall evaporates qu1ckly from the ground, leaves that look and feel rather waxy ThiS surface behaves 1n a
and that makes the so1l salty and also leaves behmd a s1m11ar way to a plastic wrapper and helps the plant to hold the
whole range of other m1nerals as well. water m. It's a wonder plant. th1s one Its JUICe has been used
as a mediCine for centunes, and even today, you can find 1t 1n
Now. desp1te th1s, deserts are home to many hv1ng th1ngs In
products on the pharmacists' shelves or 1n creams and lot1ons.
fact, they're second only to tropical rainforests 1n the vanety of
plant and an1mal spec1es that live there OK well. we're g01ng to take a closer look
So. how do plants grow 1n a place that's so dry? Well. they're
specially adapted to do th1s In fact. many of the fasc1nat1ng
features of desert plants are adaptations -these are tra1ts that
t
help the plant surv1ve 1n 1s harsh environment And desert
plants have two ma1n adaptations: the first 1s that they have an
ab1hty to collect water and to store 1t. Some have large root
systems and amazing 1nternal water-storage systems The
second adaptation IS that they have features that can actually
reduce water loss and these are often very spec1al leaf
des1gns or additiOns to the plant structure
So let's have a look at some examples Desert plants often look
very different from any other plants
OK Th1s first one IS the Saguaro Cactus. wh1ch grows 1n North
Amenca It looks a b1t like an open hand w1th long fingers Th1s
plant has a large network of roots that extend far. far away
from 1ts trunk. and these roots collect water after ram. then
the water's taken here to the green stem Th1s IS where all1ts
water IS kept, and 1t keeps the whole plant alive until the next
ram comes It's a pretty, woody plant - 1n fact, um. 1ts skeleton
IS actually used 111 bu1ld1ng matenals. so 1t's qu1te strong
Th1s next plant IS called the Barrel Cactus - named because
1t does look rather like a barrel. It can grow up to a metre m
he1ght. which IS pretty b1g, and 1t has long, yellow sp1nes. Now.
this plant has an 1nterest1ng adaptation because 1ts shape
allows 1t to expand when 1t rams - hence the barrel - and store
water 1n 1ts spongy t1ssue But then 1t shnnks 1n s1ze dunng dry
t1mes as 1t uses the stored water So that's a clever des1gn
Th1s th1rd cactus - often JUSt one plant reach1ng upwards -
has these white haws all over 1ts surface. It's called the Old
Mon Cactus because of the wh1te ha1rs. and these help the
plant reflect the hot desert sun So th1s adaptatiOn IS a water
conservation a1d 1f you like

8 Complete IELTS Bands 5-6.5