At tea, England were 184 for six in reply to South Africa's first innings 335 -- still a deficit of 151 runs.
Moeen Ali was 14 not out and Liam Dawson two not after Root, in his second match as England captain, had fallen for a fine 78 on a day when batsmen on both sides struggled in the overcast conditions.
South Africa were without fast bowler Kagiso Rababa, suspended from this match after swearing at Ben Stokes during England's 211-run win in the first of the four-match series at Lord's last week.
South Africa, 309 for six overnight, lost their last four wickets for 26 runs in 6.2 overs.
James Anderson, England's all-time leading Test wicket- taker, did the damage with a burst of four wickets for four runs in 16 balls.
But England then slumped to three for two in reply.
Former skipper Alastair Cook was caught behind for three when he got an inside edge to Vernon Philander's inswinger, although South Africa had to review Australian umpire Simon Fry's not out decision.
The South Africa-born batsman was undone by a brilliant Morkel delivery from around the wicket that cut away off the pitch and took an edge safely held by wicket-keeper Quinton de Kock -- who played in the same Johannesburg school side as Jennings.
- Root counter-attacks -
========================
Root, who made 190 in his first innings as England captain at Lord's, counter-attacked by hitting Philander for three fours in an over.
And at lunch he and Yorkshire team-mate Gary Ballance, desperate to nail down his Test place after being recalled at Lord's, had taken England to 85 for two.
The towering Morkel then had Root edging an intended drive and de Kock, diving in front of first slip, held an excellent catch.
It was the end of Root's impressive 76-ball innings, featuring 12 fours, with England now 143 for four.
De Kock was involved again when holding a juggling catch after Stokes inside-edged Maharaj onto this pad.
It took an age for Stokes to finally be given out as the umpires checked to see if the ball had made any contact with de Kock's helmet -- which would have seen the wicket chalked off.
But Maharaj bowled Bairstow with a ball that drifted in and then turned to hit off stump -- a classic left-arm spinner's wicket.
Before play started on Saturday, England persuaded the umpires to change what they believed to be an out of shape ball, with the floodlights already switched on.
It was a move that paid dividends just five balls into the day's play when, without another run added, Philander fell for his overnight 54, caught in the covers from a leading edge off Anderson.
Trent Bridge is renowned for aiding swing bowlers such as the 34-year-old Anderson, whose overall return of five for 72 in 23.2 overs was the 22nd time he'd taken five or more wickets in a Test innings and his seventh such haul at the Nottingham ground.
Disclaimer: No Business Standard Journalist was involved in creation of this content
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
