Delayed pollination and low availability of assimilates are major factors causing maize kernel abortion

Area of Science:

• Plant Biology
• Crop Science
• Agricultural Science

Background:

• Selective seed abortion is a natural survival strategy in plants, sacrificing some seeds for resource allocation.
• This phenomenon significantly impacts crop yields, presenting a challenge for agricultural productivity.
• A pollination time gap (PTG) is hypothesized to be linked to position-dependent grain abortion in crops like maize.

Purpose of the Study:

• To investigate the impact of pollination time gaps (PTGs) on maize kernel development and abortion.
• To elucidate the physiological mechanisms underlying PTG-induced grain abortion in Zea mays L.
• To develop novel methods for manipulating maize pollination patterns to study seed abortion.

Main Methods:

• Developed a novel technique to alter natural maize pollination timing.
• Compared kernel growth, invertase activity, and sugar/starch content under synchronous vs. delayed pollination.
• Utilized in situ localization to assess cell wall invertase activity in developing kernels.

Main Results:

• Synchronous pollination led to basal kernel development and apical kernel abortion.
• Delayed basal pollination suppressed basal kernel development and invertase activity, allowing apical kernel growth.
• Reduced invertase activity and sugar levels, along with altered starch distribution, were observed in delayed-pollinated kernels.

Conclusions:

• Pollination time gaps (PTGs) are a significant factor in maize grain abortion.
• PTG-induced abortion is linked to reduced sink strength and local assimilate availability in developing kernels.
• Understanding these mechanisms can inform strategies to improve crop yields by mitigating seed abortion.