Table 2.

Morphological traits of source-sink organs of wheat, influenced by LTS.

Plant organs	Effect	Growth stage	LTS intensity and duration	LTS induced alterations	References
Root	Root growth inhibited and root contact area reduced	Seedling stage (the first leaf expanded fully)	2 to 5°C (10 h) Control: 25°C	Root relative growth rate ↓	Equiza, 2001
		Seedling stage	10°C (7 d) Control: 20 and 30°C	Root length ↓ Fresh and dry root weight ↓	Buriro et al., 2011
				Root surface area ↓ Branching angle ↓ Lateral roots formation ↓	Nagel et al., 2009; Muhammad et al., 2021
Leaf	Wilting and yellowing, leaf area decreased	Approximately seven leaves stage	−5°C (1,3 d after LTS) Control: 0 d after LTS	Leaf dehydration Wilting and drooping	Han et al., 2013
		Initial seedling stage	4°C (42 d) Control: 4°C	Leaf number ↓ Flag leaf area ↓ Leaf biomass ↓ *Specific leaf area ↓	Valluru et al., 2012
		Seedling stage (three-leaf stage)	2 to 5°C (10 h) Control: 25°C	Leaf area ↓ Leaf thickness ↑	Equiza, 2001
Spike	Spike growth inhibited and grain yield decreased	Six leaf stage, or jointing stage	−3°C (24, 30, and 48 h) Control: 24°C/16°C, day/night	Discoloration and degeneration Spike length ↓	Koo et al., 2008
		Jointing and booting stages	Mean temperature: −6 ~ 2°C (2,4 and 6 d) Control: 6°C	Grain length (L) and width (W) ↓ The grain L/W ratio ↑ Grain appearance quality ↓ *SNPP, GNPP and grain weight ↓ Grain yield and harvest index ↓	Liu et al., 2019a,b

^*Specific leaf area, expressed as leaf area/fresh weight or as leaf area/dry weight; SNPP, spike number per plant; GNPP, grain number per plant (Here, ↓ indicates a decrease and ↑ indicates an increase).