Table 3.

Number of plasmodesmata showing swelling of sphincter among plasmodesmata at mesophyll/bundle sheath interfaces in seedlings of two maize inbred lines chilled (14 °C) for different time periods

	KW 1074										CM 109
	Control		1 h		4 h		12 h		28 h		C		1 h		4 h		12 h		28 h		Example
Total examined:	137		175		162		311		142		153		386		315		186		133
Not defined	Mean	% of total	Mean	% of total	Mean	% of total	Mean	% of total	Mean	% of total	Mean	% of total	Mean	% of total	Mean	% of total	Mean	% of total	Mean	% of total
	30	21·9	70	40·0	24	14·8	82	26·4	34	23·9	45	29·4	127	32·9	118	37·5	40	21·5	40	30·1
Therefore total analysed	107		105		138		229		108		108		259		197		146		93
Opened	107		100		130		221		105		108		216		140		109		71
Closed	Mean	% of total analysed	Mean	% of total analysed	Mean	% of total analysed	Mean	% of total analysed	Mean	% of total analysed	Mean	% of total analysed	Mean	% of total analysed	Mean	% of total analysed	Mean	% of total analysed	Mean	% of total analysed
	0	0	5	4·8	8	5·8	8	3·5	3	2·8	0	0	43*	16·6	57*	28·9	37*	25·3	22*	23·7

1 h, 4 h, 12 h, 28 h, time of chilling; see Materials and methods.

Data were collected in six independent experiments.

* Significant differences (P < 0·05) estimated by chi-square test.