The Physiological Responses of Maize Seedlings with Different Amylose Content to Drought Stress

Abstract

In this study, we investigated the physiological responses of maize with different amylose content at seedlings to drought stress. For waxy maize (WMS) and normal maize (NMS), the decline of photosynthesis under drought stress (DS) was due to the stomatal limitation. DS increased the non-photochemical quenching coefficient (NPQ), whereas decreased the activities of peroxidase (POD) and the plant height (PH), compared with the plants under normal irrigation. The content of starch increased and decreased significantly upon moderate and severe drought stress, respectively. For high amylose maize (HAMSs), they showed stomatal limitation upon moderate stress, while non-stomatal limitation upon severe stress. The NPQ and POD showed contrary trend compared with WMS and NMS. DS significantly decreased the starch content and PH of them. The principal component analysis (PCA) showed HAMSs were more sensitive to drought than WMS and NMS. The GBSSIIa level of HAMSs was also lower than that of WMS and NMS. Therefore, we conclude that HAMSs respond to DS through redox regulation to avoid oxidative damage, whereas WMS and NMS by increasing starch biosynthesis, and the higher GBSSIIa level may produce more amylose, which could promote the growth of maize under drought effectively.

A new insight into the biosynthesis, structure, and functionality of waxy maize starch under drought stress

“…Natural drying started after pollination, and the drought level was controlled and calculated by weighing each pot at 08:00 and 18:00 every day and adding the water required in a timely fashion based on the WHC of these soils (4.5 kg) 8 . The sample irrigated under normal level was kept with 70% WHC, whereas the DS one was set with 50% WHC.…”

“…Natural drying started after pollination, and the drought level was controlled and calculated by weighing each pot at 08:00 and 18:00 every day and adding the water required in a timely fashion based on the WHC of these soils (4.5 kg). 8 The sample irrigated under normal level was kept with 70% WHC, whereas the DS one was set with 50% WHC. Once the target water level was reached, the samples were treated under these levels for another 30 days, and the required water was supplemented in a timely fashion.…”

“…Crop grains are the main source of starch, including maize, wheat, and rice etc 7 . It is true that these plants may suffer different abiotic stresses during their whole growth period, such as drought, high temperature, and salt 8 . And drought stress (DS) is the major one of these stresses 9 .…”

“…7 It is true that these plants may suffer different abiotic stresses during their whole growth period, such as drought, high temperature, and salt. 8 And drought stress (DS) is the major one of these stresses. 9 There is no doubt that DS will affect the development of crop grains and the biosynthesis of starch.…”

Melatonin Mitigates Water Deficit Stress in Cenchrus alopecuroides (L.) Thunb through Up-Regulating Gene Expression Related to the Photosynthetic Rate, Flavonoid Synthesis, and the Assimilatory Sulfate Reduction Pathway

“…A water deficit can cause changes in plant cell metabolism, resulting in the excessive accumulation of reactive oxygen species and lipid peroxidation, inhibiting plant photosynthesis and cell division, and ultimately leading to growth retardation and stagnation [2,3]. Developing effective solutions to mitigate the effects of water deficit on plants is critical [4]. Plants themselves have various mechanisms to combat stress by activating defense genes, encoding proteins involved in defense pathways, and activating antioxidant defense systems [5,6].…”