▁ ▁DNA ▁contains ▁a ▁large ▁quantity ▁of ▁ph osph orus ▁in ▁the ▁ph osph odi ester ▁link ages ▁between ▁bases ▁in ▁the ▁o lig on uc le ot ide ▁chain . ▁DNA ▁can ▁therefore ▁be ▁track ed ▁by ▁replacing ▁the ▁ph osph orus ▁with ▁ph osph orus - 3 2 . ▁This ▁technique ▁is ▁extens ively ▁used ▁in ▁Southern ▁bl ot ▁analysis ▁of ▁DNA ▁samples . ▁In ▁this ▁case ▁a ▁ph osph orus - 3 2 - cont aining ▁DNA ▁pro be ▁hy brid ises ▁to ▁its ▁complement ary ▁sequence ▁where ▁it ▁appears ▁in ▁a ▁gel . ▁Its ▁location ▁can ▁then ▁be ▁detected ▁by ▁phot ographic ▁film . ▁ ▁Plant ▁sciences ▁Ph osph orus - 3 2 ▁is ▁used ▁in ▁plant ▁sciences ▁for ▁tracking ▁a ▁plant ' s ▁u pt ake ▁of ▁fert il iser ▁from ▁the ▁roots ▁to ▁the ▁leaves . ▁ ▁The ▁ph osph orus - 3 2 - label led ▁fert il iser ▁is ▁given ▁to ▁the ▁plant ▁hydro pon ically ▁or ▁via ▁water ▁in ▁the ▁soil ▁and ▁the ▁usage ▁of ▁the ▁ph osph orus ▁can ▁be ▁mapped ▁from ▁the ▁em itted ▁beta ▁radiation . ▁The ▁information ▁gathered ▁by ▁mapping ▁the ▁fert il iser ▁u pt ake ▁show ▁how ▁the ▁plant ▁takes ▁up ▁and ▁uses ▁the ▁ph osph orus ▁from ▁fert il iser . ▁ ▁Saf ety ▁The ▁high ▁energy ▁of ▁em itted ▁beta ▁particles ▁and ▁the ▁low ▁half - life ▁of ▁ph osph orus - 3 2 ▁make ▁it ▁potentially ▁harm ful ; ▁its ▁maximum ▁specific ▁activity ▁is ▁